Gibbous: A Cthulhu Adventure is a comedic point 'n click game that pays homage to classic Lucas adventures, HP Lovecraft, Hitchcock, and more. The game features three protagonists navigating through strange cultists, ancient voodoo, and the enigmatic presence of Dead Cthulhu. The storyline revolves around the mysterious Necronomicon and its impact on the characters' lives.

In the game, players control grizzled detective Don R. Ketype, determined to acquire the Necronomicon, and the carefree librarian Buzz Kerwan, who accidentally transforms his cat into a talking abomination. This sets them on a quest to restore Kitteh back to her feline form, leading to a whimsical and intriguing adventure.