Infiltrate! Secret of the Haunted Castle (潜入!ゆうれい城の秘密, Sennyū! Yūrei shiro no himitsu), known as simply The Haunted Castle (or the Haunted Hammerlock Castle) in most dubs, is the first episode of the 1992 anime series of Calimero.
In this episode, Mr. Critichelli takes Calimero and friends to an old castle, and after hearing it is haunted, they want to investigate and try to find ghosts.