Angel's Lullaby takes place during the game's opening introduction, back during the Human and Monster War. Expanding on the lore, meta narrative and core themes of the original games, Angel's aims to enrich the Undertale world by mixing both the old and new. Combining both an open-world and linear story-line, Angel's is an ambitious fangame with a large story to tell. There's three main "Acts," each with it's own main area that follows a story.