diff --git a/README.md b/README.md
index dd7478a..4caf630 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@
 Steam Deck fan controls.
 
 This is generated from the template plugin for the [SteamOS Plugin Loader](https://github.com/SteamDeckHomebrew/PluginLoader).
+You will need that installed for this plugin to work.
 
 ## License
 
diff --git a/main.py b/main.py
index 46c29c2..8544e70 100644
--- a/main.py
+++ b/main.py
@@ -1,12 +1,174 @@
-class Plugin:
-    # A normal method. It can be called from JavaScript using call_plugin_function("method_1", argument1, argument2)
-    async def method_1(self, *args):
-        pass
+import json
+import os
+import asyncio
 
-    # A normal method. It can be called from JavaScript using call_plugin_function("method_2", argument1, argument2)
-    async def method_2(self, *args):
-        pass
+import logging
+
+logging.basicConfig(
+    filename = "/home/deck/.fantastic.log",
+    format = '%(asctime)s %(levelname)s %(message)s',
+    filemode = 'w',
+    force = True)
+
+logger = logging.getLogger()
+logger.setLevel(logging.DEBUG)
+
+FAN_MINIMUM = 0
+FAN_MAXIMUM = 7000 # max is more around 7100
+
+TEMPERATURE_MINIMUM = 0.0
+TEMPERATURE_MAXIMUM = 100.0
+
+DATA_SAVE_FILE = "fantastic.json"
+DATA_SAVE_FOLDER = "/home/deck/.config/fantastic/"
+DATA_SAVE_PATH = DATA_SAVE_FOLDER + DATA_SAVE_FILE
+
+DEFAULT_DATA = {
+    "version": 0,
+    "enable": False,
+    "interpolate": False,
+    "curve": [],
+}
+
+class Plugin:
+    settings = None
+    is_changed = False
+
+    plot_width = 1;
+    plot_height = 1;
+
+    period_s = 1.0;
+
+    async def set_curve(self, curve):
+        await self.wait_for_ready(self)
+        self.settings["curve"] = curve
+        self.is_changed = True
+
+    async def get_curve(self):
+        await self.wait_for_ready(self)
+        return self.settings["curve"]
+
+    async def get_curve_point(self, index):
+        await self.wait_for_ready(self)
+        return self.settings["curve"][index]
+
+    async def set_curve_point(self, index, point):
+        await self.wait_for_ready(self)
+        self.settings["curve"][index] = point
+        self.is_changed = True
+
+    async def add_curve_point(self, point):
+        await self.wait_for_ready(self)
+        self.settings["curve"].append(point)
+        self.settings["curve"].sort(key=lambda p: p["x"])
+        self.is_changed = True
+        x = point["x"]
+        y = point["y"]
+        logger.debug(f"Added point (Temp:{100*x},PWM%:{100*y}) ~= ({x*self.plot_width},{y*self.plot_height})")
+
+    async def remove_curve_point(self, index):
+        await self.wait_for_ready(self)
+        del(self.settings["curve"][index])
+        self.is_changed = True
+
+    async def set_enable(self, enable: bool):
+        await self.wait_for_ready(self)
+        self.settings["enable"] = enable
+        on_set_enable(enable)
+        self.is_changed = True
+
+    async def get_enable(self) -> bool:
+        await self.wait_for_ready(self)
+        return self.settings["enable"]
+
+    async def set_plot_size(self, x, y):
+        logging.debug(f"Set plot size to ({x},{y})")
+        self.plot_width = x
+        self.plot_height = y
+
+    async def set_poll_period(self, period):
+        self.period_s = period
+
+    def save(self):
+        if not os.path.exists(DATA_SAVE_FOLDER):
+            os.mkdir(DATA_SAVE_FOLDER)
+        with open(DATA_SAVE_PATH, "w") as data_file :
+            json.dump(self.settings, data_file)
+
+    async def wait_for_ready(self):
+        while self.settings is None:
+            await asyncio.sleep(0.01)
+
+    def do_fan_control(self):
+        index = -1
+        curve = self.settings["curve"]
+        temperature = (thermal_zone(0) - TEMPERATURE_MINIMUM) / TEMPERATURE_MAXIMUM
+        for i in range(len(curve)-1, -1, -1):
+            if curve[i]["x"] < temperature:
+                index = i
+                break
+        if index != -1:
+            target_speed = ((1 - curve[index]["y"]) * FAN_MAXIMUM) + FAN_MINIMUM
+            set_fan_target(int(target_speed))
+        else:
+            if len(curve) == 0:
+                set_fan_target(int(FAN_MAXIMUM))
+            else:
+                set_fan_target(int((FAN_MINIMUM + FAN_MAXIMUM) / 2))
 
     # Asyncio-compatible long-running code, executed in a task when the plugin is loaded
     async def _main(self):
-        pass
\ No newline at end of file
+        # startup
+        if os.path.exists(DATA_SAVE_PATH):
+            with open(DATA_SAVE_PATH, "r") as data_file:
+                self.settings = json.load(data_file)
+        else:
+            self.settings = dict(DEFAULT_DATA)
+        try:
+            self.settings["version"]
+        except:
+            self.settings = dict(DEFAULT_DATA)
+        while self.settings["version"] != DEFAULT_DATA["version"]:
+            # TODO specific upgrade functionality
+            self.settings["version"] = DEFAULT_DATA["version"]
+            self.settings["enable"] = DEFAULT_DATA["enable"]
+            self.settings["interpolate"] = DEFAULT_DATA["interpolate"]
+            self.settings["curve"] = DEFAULT_DATA["curve"]
+            self.is_changed = True
+        on_set_enable(self.settings["enable"])
+        # work loop
+        while True:
+            if self.is_changed:
+                self.save(self)
+                self.is_changed = False
+            if self.settings["enable"]:
+                # custom fan curve is enabled
+                self.do_fan_control(self)
+            await asyncio.sleep(self.period_s)
+
+def thermal_zone(index: int):
+    with open(f"/sys/class/thermal/thermal_zone{index}/temp", "r") as f:
+        result = float(f.read().strip()) / 1000.0
+        logging.debug(f"Got {result}'C from thermal_zone{index}")
+        return result
+
+def set_fan_target(rpm: int):
+    logging.debug(f"Setting fan1_target to {rpm}")
+    with open("/sys/class/hwmon/hwmon5/fan1_target", "w") as f:
+        f.write(str(rpm))
+
+def on_enable():
+    with open("/sys/class/hwmon/hwmon5/recalculate", "w") as f:
+        f.write("1")
+    # TODO disable system fan control
+
+def on_disable():
+    with open("/sys/class/hwmon/hwmon5/recalculate", "w") as f:
+        f.write("0")
+    # TODO restart system fan control
+
+def on_set_enable(enable):
+    if enable:
+        on_enable()
+    else:
+        on_disable()
diff --git a/main_view.html b/main_view.html
index c1e11dd..b7e4865 100644
--- a/main_view.html
+++ b/main_view.html
@@ -5,10 +5,164 @@
         <link rel="stylesheet" href="/steam_resource/css/library.css">
         <script src="/static/library.js"></script>
         <script>
-            async function onload() {}
+            const PLOT_HEIGHT = 200;
+            const PLOT_WIDTH = 284;
+            const OFFSET_X = 0;
+            const OFFSET_Y = 0;
+            // state
+            let curve = [];
+            let plotClickIsHandled = false;
+
+            // back-end
+
+            function setCurve(curve) {
+                return call_plugin_method("set_curve", {"curve": curve});
+            }
+
+            function getCurve() {
+                return call_plugin_method("get_curve", {});
+            }
+
+            function getCurvePoint(index) {
+                return call_plugin_method("get_curve_point", {"index": index});
+            }
+
+            function setCurvePoint(index, point) {
+                return call_plugin_method("set_curve_point", {"index": index, "point": point});
+            }
+
+            function addCurvePoint(point) {
+                return call_plugin_method("add_curve_point", {"point": point});
+            }
+
+            function removeCurvePoint(index) {
+                return call_plugin_method("remove_curve_point", {"index": index});
+            }
+
+            function setEnable(enable) {
+                return call_plugin_method("set_enable", {"enable": enable});
+            }
+
+            function getEnable() {
+                return call_plugin_method("get_enable", {});
+            }
+
+            function setPlotSize(x, y) {
+                return call_plugin_method("set_plot_size", {"x": x, "y": y});
+            }
+
+            // events
+
+            async function onload_body() {
+                let graphDiv = document.getElementById("graphDiv");
+                await setPlotSize(PLOT_WIDTH, PLOT_HEIGHT);
+                const state_controlToggle = await getEnable(); // retrieve from back-end
+                setToggleState(document.getElementById("controlToggle"), state_controlToggle);
+                showHideElement(graphDiv, state_controlToggle);
+                if (state_controlToggle) {
+                    curve = await getCurve();
+                    buildCurvePlot(curve);
+                }
+                console.log("Loaded");
+            }
+
+            async function onclick_graphDiv(e) {
+                console.log("Click @ (" + e.layerX.toString() + ", " + e.layerY.toString() + ")");
+                if (plotClickIsHandled) {
+                    plotClickIsHandled = false;
+                } else {
+                    await addCurvePoint({"x": (e.layerX - OFFSET_X) / PLOT_WIDTH, "y": (e.layerY - OFFSET_Y) / PLOT_HEIGHT});
+                    curve = await getCurve();
+                    buildCurvePlot(curve);
+                }
+            }
+
+            async function onclick_controlToggle() {
+                console.log("Click @ controlToggle");
+                let graphDiv = document.getElementById("graphDiv");
+                let controlToggle = document.getElementById("controlToggle");
+                const state_controlToggle = getToggleState(controlToggle);
+                await setEnable(!state_controlToggle); // notify back-end
+                setToggleState(controlToggle, !state_controlToggle);
+                showHideElement(graphDiv, !state_controlToggle);
+                if (!state_controlToggle) {
+                    curve = await getCurve();
+                    buildCurvePlot(curve);
+                }
+            }
+
+            async function onclick_plotPoint(e, index) {
+                console.log("Click @ plotPoint " + index.toString());
+                plotClickIsHandled = true; // this must be before the first async call (janky!)
+                await removeCurvePoint(index);
+                curve = await getCurve();
+                buildCurvePlot(curve);
+                //e.stopPropogation();
+            }
+
+            // common
+
+            function buildCurvePlot(curve_points) {
+                // TODO
+                let graphDiv = document.getElementById("graphDiv");
+                let newStr = "<span style=\"font-size:x-small;position:absolute;left:0px;top:0px;\">100%</span><span style=\"font-size:x-small;position:absolute;left:0px;bottom:0px;\">0</span><span style=\"font-size:x-small;position:absolute;left:0px;bottom:50%;writing-mode:vertical-lr;text-orientation:mixed;\">Fan</span><span style=\"font-size:x-small;position:absolute;right:0px;bottom:0px;\">100</span><span style=\"font-size:x-small;position:absolute;left:35%;bottom:0px;\">Temperature (C)</span>";
+                for (let i = 0; i < curve_points.length; i++) {
+                    const point = curve_points[i];
+                    newStr += "<span style=\"position:absolute;"
+                    newStr += "top:" + Math.round(point["y"]*PLOT_HEIGHT + OFFSET_Y).toString() + "px;left:" + Math.round(point["x"]*PLOT_WIDTH + OFFSET_X).toString() + "px;";
+                    newStr += "width:8px;height:8px;background-color:red;\" id=\"plotPoint";
+                    newStr += i.toString() + "\" onclick=\"onclick_plotPoint(event," + i.toString() + ")\"></span>";
+                }
+                graphDiv.innerHTML = newStr;
+            }
+
+            function showHideElement(elem, visible) {
+                if (visible) {
+                    elem.style.visibility = "visible";
+                } else {
+                    elem.style.visibility = "hidden";
+                }
+            }
+
+            function setToggleState(toggle, state) {
+                const ENABLED_CLASS = "gamepaddialog_On_yLrDA";
+                if (state && !toggle.classList.contains(ENABLED_CLASS)) {
+                    toggle.classList.add(ENABLED_CLASS);
+                }
+
+                if (!state && toggle.classList.contains(ENABLED_CLASS)) {
+                    toggle.classList.remove(ENABLED_CLASS);
+                }
+            }
+
+            function getToggleState(toggle) {
+                return toggle.classList.contains("gamepaddialog_On_yLrDA");
+            }
         </script>
     </head>
-    <body onload="onload()">
-        <h2>Hello World</h2>
+    <body onload="onload_body()">
+        <div class="quickaccessmenu_TabGroupPanel_1QO7b Panel Focusable">
+            <div class="quickaccesscontrols_PanelSectionRow_26R5w">
+                <div class="quickaccesscontrols_PanelSectionRow_26R5w">
+                    <div class="gamepaddialog_Field_eKmEX gamepaddialog_WithFirstRow_2bDqk gamepaddialog_ExtraPaddingOnChildrenBelow_3nLNL gamepaddialog_StandardPadding_xIITX gamepaddialog_HighlightOnFocus_2HFrm Panel Focusable" style="--indent-level:0;">
+                        <div class="gamepaddialog_FieldLabelRow_2VcTl">
+                            <div class="gamepaddialog_FieldLabel_3jMlJ">
+                                Custom Fan Curve
+                            </div>
+                            <div class="gamepaddialog_FieldChildren_2rhav">
+                                <div id="controlToggle" tabindex="0" class="gamepaddialog_Toggle_9Ql-o Focusable" onclick="onclick_controlToggle()">
+                                    <div class="gamepaddialog_ToggleRail_2bl0i"></div>
+                                    <div class="gamepaddialog_ToggleSwitch_1PQpp"></div>
+                                </div>
+                            </div>
+                        </div>
+                        <div class="gamepaddialog_FieldDescription_1W1to">Overrides SteamOS fan curve</div>
+                    </div>
+                </div>
+            </div>
+        </div>
+        <div id="graphDiv" style="height:200px;width:284px;border:2px solid red;position:relative;" onclick="onclick_graphDiv(event)">
+            Some text to show that something is broken :(
+        </div>
     </body>
 </html>