diff --git a/crates/treehouse/src/generate.rs b/crates/treehouse/src/generate.rs
index 339505d..21bc43f 100644
--- a/crates/treehouse/src/generate.rs
+++ b/crates/treehouse/src/generate.rs
@@ -20,7 +20,10 @@ use crate::{
     parse::parse_tree_with_diagnostics,
     state::{report_diagnostics, Source},
     tree::SemaRoots,
-    vfs::{self, Cd, Dir, DirEntry, DynDir, MemDir, Overlay, ToDynDir, VPath, VPathBuf},
+    vfs::{
+        self, Cd, ContentCache, Dir, DirEntry, DynDir, EditPath, ImageSize, MemDir, Overlay,
+        ToDynDir, VPath, VPathBuf,
+    },
 };
 
 use crate::state::{FileId, Treehouse};
@@ -415,14 +418,10 @@ impl Dir for TreehouseDir {
         } else {
             path
         };
-        let mut path = path.to_owned();
-        if path.extension() == Some("html") {
-            path.set_extension("");
-        }
 
         self.sources
             .parsed_trees
-            .get(&path)
+            .get(path)
             .map(|parsed_tree| {
                 generate_tree_or_error(&self.sources, &self.dirs, &self.handlebars, parsed_tree)
                     .into()
@@ -456,12 +455,67 @@ impl fmt::Debug for TreehouseDir {
     }
 }
 
+struct HtmlCanonicalize<T> {
+    inner: T,
+}
+
+impl<T> HtmlCanonicalize<T> {
+    pub fn new(inner: T) -> Self {
+        Self { inner }
+    }
+}
+
+impl<T> Dir for HtmlCanonicalize<T>
+where
+    T: Dir,
+{
+    fn dir(&self, path: &VPath) -> Vec<DirEntry> {
+        self.inner.dir(path)
+    }
+
+    fn content(&self, path: &VPath) -> Option<Vec<u8>> {
+        let mut path = path.to_owned();
+        if path.extension() == Some("html") {
+            path.set_extension("");
+        }
+
+        self.inner.content(&path)
+    }
+
+    fn content_version(&self, path: &VPath) -> Option<String> {
+        self.inner.content_version(path)
+    }
+
+    fn image_size(&self, path: &VPath) -> Option<ImageSize> {
+        self.inner.image_size(path)
+    }
+
+    fn anchor(&self, path: &VPath) -> Option<VPathBuf> {
+        self.inner.anchor(path)
+    }
+
+    fn edit_path(&self, path: &VPath) -> Option<EditPath> {
+        self.inner.edit_path(path)
+    }
+}
+
+impl<T> fmt::Debug for HtmlCanonicalize<T>
+where
+    T: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "HtmlCanonicalize({:?})", self.inner)
+    }
+}
+
 pub fn target(dirs: Arc<Dirs>, sources: Arc<Sources>) -> DynDir {
     let mut root = MemDir::new();
     root.add(VPath::new("static"), dirs.static_.clone());
 
     let dir_index = DirIndex::new(sources.parsed_trees.keys().map(|x| &**x));
     let tree_view = TreehouseDir::new(dirs, sources, dir_index);
+    let tree_view = ContentCache::new(tree_view);
+    let tree_view = HtmlCanonicalize::new(tree_view);
 
     Overlay::new(tree_view.to_dyn(), root.to_dyn()).to_dyn()
 }
diff --git a/crates/treehouse/src/vfs.rs b/crates/treehouse/src/vfs.rs
index 124e730..9ff75d9 100644
--- a/crates/treehouse/src/vfs.rs
+++ b/crates/treehouse/src/vfs.rs
@@ -52,6 +52,7 @@ use std::{
 mod anchored;
 pub mod asynch;
 mod cd;
+mod content_cache;
 mod content_version_cache;
 mod edit;
 mod empty;
@@ -64,6 +65,7 @@ mod physical;
 
 pub use anchored::*;
 pub use cd::*;
+pub use content_cache::*;
 pub use content_version_cache::*;
 pub use edit::*;
 pub use empty::*;
diff --git a/crates/treehouse/src/vfs/content_cache.rs b/crates/treehouse/src/vfs/content_cache.rs
new file mode 100644
index 0000000..8c4a44a
--- /dev/null
+++ b/crates/treehouse/src/vfs/content_cache.rs
@@ -0,0 +1,60 @@
+use std::fmt::{self, Debug};
+
+use dashmap::DashMap;
+
+use super::{Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
+
+pub struct ContentCache<T> {
+    inner: T,
+    cache: DashMap<VPathBuf, Option<Vec<u8>>>,
+}
+
+impl<T> ContentCache<T> {
+    pub fn new(inner: T) -> Self {
+        Self {
+            inner,
+            cache: DashMap::new(),
+        }
+    }
+}
+
+impl<T> Dir for ContentCache<T>
+where
+    T: Dir,
+{
+    fn dir(&self, path: &VPath) -> Vec<DirEntry> {
+        self.inner.dir(path)
+    }
+
+    fn content(&self, path: &VPath) -> Option<Vec<u8>> {
+        self.cache
+            .entry(path.to_owned())
+            .or_insert_with(|| self.inner.content(path))
+            .clone()
+    }
+
+    fn content_version(&self, path: &VPath) -> Option<String> {
+        self.inner.content_version(path)
+    }
+
+    fn image_size(&self, path: &VPath) -> Option<ImageSize> {
+        self.inner.image_size(path)
+    }
+
+    fn anchor(&self, path: &VPath) -> Option<VPathBuf> {
+        self.inner.anchor(path)
+    }
+
+    fn edit_path(&self, path: &VPath) -> Option<EditPath> {
+        self.inner.edit_path(path)
+    }
+}
+
+impl<T> fmt::Debug for ContentCache<T>
+where
+    T: Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "ContentCache({:?})", self.inner)
+    }
+}
diff --git a/static/js/tree.js b/static/js/tree.js
index a8428f1..ea7e924 100644
--- a/static/js/tree.js
+++ b/static/js/tree.js
@@ -104,9 +104,7 @@ class LinkedBranch extends Branch {
 
     async loadTreePromise(_initiator) {
         try {
-            let response = await fetch(
-                `${TREEHOUSE_SITE}/${this.linkedTree}.html`
-            );
+            let response = await fetch(`${TREEHOUSE_SITE}/${this.linkedTree}`);
             if (response.status == 404) {
                 throw `Hmm, seems like the tree "${this.linkedTree}" does not exist.`;
             }
@@ -127,7 +125,9 @@ class LinkedBranch extends Branch {
                 // No need to await for the import because we don't use the resulting module.
                 // Just fire and forger 💀
                 // and let them run in parallel.
-                let url = URL.createObjectURL(new Blob([script.textContent], { type: "text/javascript" }))
+                let url = URL.createObjectURL(
+                    new Blob([script.textContent], { type: "text/javascript" }),
+                );
                 import(url);
             }
         } catch (error) {
@@ -257,10 +257,7 @@ async function expandLinkedBranch() {
     let currentlyHighlightedBranch = getCurrentlyHighlightedBranch();
     if (currentlyHighlightedBranch.length > 0) {
         let linkedBranch = document.getElementById(currentlyHighlightedBranch);
-        if (
-            linkedBranch.children.length > 0 &&
-            linkedBranch.children[0].tagName == "DETAILS"
-        ) {
+        if (linkedBranch.children.length > 0 && linkedBranch.children[0].tagName == "DETAILS") {
             expandDetailsRecursively(linkedBranch.children[0]);
         }
     }