16. Mr. Monk Goes to Jail

When a death row inmate is fatally poisoned 45 minutes before his scheduled execution, Monk visits the prison to investigate the case. His nemesis, Dale the Whale ( Tim Curry ), offers to tell Monk everything he knows about Trudy's death if Monk finds the killer. Acting on a tip from the prison librarian ( Kathy Baker ), Monk goes undercover as an inmate and is assigned to a cell with a quadruple murderer ( Danny Trejo ), whom he becomes friends with.