The Search of Mickey Mouse

The Search of Mickey Mouse was a planned animated film from Disney. It was announced to commemorate Mickey Mouse's 75th birthday.

Plot
Mickey Mouse is kidnapped by unknown forces, forcing Minnie Mouse to enlist Basil of Baker Street to investigate his disappearance. Along the way, they encounter one character from Disney's animated film canon including Alice, Peter Pan, Robin Hood, and Aladdin.

Why It Was Cancelled
The project suffered script problems with the multiple cameos being deemed too complex.

Result
The film was shelved and replaced with a new feature film, Mickey, Donald, Goofy: The Three Musketeers.