Martha Takes the Cake / Codename: Martha

S1 E3: It’s Alice’s birthday and everybody’s invited, including Martha. The only problem is that Nelson (Martha’s cat nemesis) will be there too. When somebody—or some animal—ruins the birthday cake, Alice’s brother Ronald thinks Martha’s responsible. Martha proclaims her innocence . . . but why was she surrounded by cake crumbs? / Martha, Helen, and T.D. uncover a plot to rob the jewelry store, or so they think until their two suspects turn out to be police detectives on a stakeout. Now that everybody has gone home in disgrace, how will Martha catch the real criminals?