How do they solve a mystery when they don't have a clue?

Looney Tunes: Back in Action (2003)

Directed by Joe Dante

Fed up with all the attention going to Bugs Bunny, Daffy Duck quits Hollywood, teams up with recently-fired stuntman Damien Drake Jr. and embarks on a round-the-world adventure, along with Bugs and The VP of Warner Bros. Their mission? Find Damien's father, and the missing blue diamond... and stay one step ahead of The Acme Corp., who wants the diamond for their own purposes.