From Wikipedia:

Monkey Island 2: LeChuck's Revenge is an adventure game developed and published by LucasArts in 1991. It was the second game of the Monkey Island series, following The Secret of Monkey Island, and the sixth LucasArts game to use the SCUMM engine. It was the first game to use the iMUSE sound system.

The game's story centers on the wannabe pirate Guybrush Threepwood. After defeating ghost pirate LeChuck in The Secret of Monkey Island, little is known of what happened between Guybrush Threepwood and Elaine Marley. The sequel involves Guybrush's attempts to find the mysterious treasure of Big Whoop.