diff --git a/src/features/flattenThreads/presentation/scripts/setUpReplyActionHandler.script.ts b/src/features/flattenThreads/presentation/scripts/setUpReplyActionHandler.script.ts
new file mode 100644
index 0000000..b62140e
--- /dev/null
+++ b/src/features/flattenThreads/presentation/scripts/setUpReplyActionHandler.script.ts
@@ -0,0 +1,20 @@
+import Script from '../../../../common/architecture/scripts/Script';
+import InjectLitComponentsScript from '../../../../presentation/standaloneScripts/litComponents/injectLitComponents.script';
+import FlattenThreadsReplyActionHandler from '../../core/replyActionHandler';
+
+export default class FlattenThreadsSetUpReplyActionHandlerScript extends Script {
+  page: never;
+  environment: never;
+  runPhase: never;
+  runAfter = [InjectLitComponentsScript];
+
+  constructor(
+    private flattenThreadsReplyActionHandler: FlattenThreadsReplyActionHandler,
+  ) {
+    super();
+  }
+
+  execute() {
+    this.flattenThreadsReplyActionHandler.handleIfApplicable();
+  }
+}
diff --git a/src/features/flattenThreads/presentation/scripts/styles.script.ts b/src/features/flattenThreads/presentation/scripts/styles.script.ts
new file mode 100644
index 0000000..338adb2
--- /dev/null
+++ b/src/features/flattenThreads/presentation/scripts/styles.script.ts
@@ -0,0 +1,12 @@
+import Script from '../../../../common/architecture/scripts/Script';
+import { injectStylesheet } from '../../../../common/contentScriptsUtils';
+
+export default class FlattenThreadsStylesScript extends Script {
+  page: never;
+  environment: never;
+  runPhase: never;
+
+  execute() {
+    injectStylesheet(chrome.runtime.getURL('css/flatten_threads.css'));
+  }
+}