Mickey Mouse: Disney Animated Shorts

The Chain Gang (1x21)

Air date: Sep 05, 1930

The first appearance of Pluto, surprisingly enough as one of the hounds who chases Mickey after his escape. Mickey's a prisoner on jailer Pegleg Pete's rock pile. In a riot, he escapes, but when he's pursued by the jail guards' hounds, he jumps on a pair of motley horses who finally return him to jail the hard way.