Set the content in the second heading to "An Old Hope".

<html><body><h1 id="mainTitle">Star Conflicts</h1><h2 id="chapter1">An old hope</h2><p> A long time ago, in a galaxy far, far, away...</p><script>document.getElementById("chapter1").innerHTML = "An Old Hope";</script>
</body>
</html>]]>

Make sure to choose "chapter1".