diff --git a/fish/ds-patch b/fish/ds-patch
new file mode 100644
index 0000000..084bc11
--- /dev/null
+++ b/fish/ds-patch
@@ -0,0 +1,14 @@
+#!/usr/bin/env fish
+
+function ds-patch -d 'Patches a Nintendo DS game' -a zip xp
+	set out (basename "$zip" .zip).nds
+	set tmp (mktemp -d)
+
+	unzip "$zip" -d "$tmp"
+	xdelta3 -d -s "$tmp/"*.nds "$xp" "$tmp/patched.nds"
+	ndstrim "$tmp/patched.nds" "$out"
+
+	rm -rf "$tmp"
+end
+
+## EOF