Warner and Charlotte Burton are throwing a birthday party for their daughter on her 18th birthday. After Thames the butler brings out the birthday cake and Terri blows it out, her boyfriends Kingsley Adderson asks to speak to her in the Japanese garden. He wants to know if she's going to accept his marriage proposal but Terri isn't ready to give him an answer. Suddenly a masked man emerges from the bushes, knocks out Kingsley, and kidnaps Terri.
Frank is in the process of bringing in a chimpanzee responsible for zoo murders when he gets called to the Burton manor. Ed tells him that the kidnapper tied a note to a window and threw it into the rock garden. They check out the abduction scene and Ed confirms Kingsley has gone to the hospital. They talk to Warner and Charlotte, but are interrupted when the kidnapper calls. Norberg tries to put a tap on the phone while Charlotte stalls for time. She fails and the kidnapper hangs up after telling her she'll call with instructions later. Norberg is unable to trace the call and Ed and Frank leave him to watch the Burtons.
The next day, Frank talks to Kingsley at the basketball court where he plays. Frank brings up the engagement and Kingsley admits that Terri was reluctant to marry him. The detective wonders if Kingsley was trying to inherit Terri's money, but Kingsley insists he loved Terri. Frank determines that Kingsley owes money to the mob, but there's nothing definite to connect him to the kidnapping.
The kidnapper sends a tape to the manor with a recording to confirm Terri is alive. Norberg adjusts the speakers to filter out the background noise. There are no instructions for delivering the ransom money on the tape, but suddenly the kidnapper throws a mime through the window. They play Charades and eventually learn they're to drop off $1 million at a bus depot at 10 o'clock on Thursday.
At Police Squad, Frank checks with Ted who reveals that the tape has the sounds of a bell a foghorn in the background. They figure the tape was made in the lakefront. As they take the elevator, Frank briefs Ed on the news and worry that Warner won't be bale to raise the ransom money in time. Police Squad launches a search of the lakefront, but even the bikini-clad aerobic girls that Frank talks to know nothing. He returns to Police Squad to reassure Warner, who has arrived with the money.
As Frank and Ed drive around for no particular reason, they hear the sound of a bell at a gas station and figure they're on the wrong track. They listen to Ed's tuba music 8-track and realize the foghorn is a tuba, so they start searching all tuba-related stores that have a gas station nearby. They turn up nothing, so Frank talks to Johnny and learns there's a new tuba club, El Tubalero, in town. Frank goes to the club and spots a masked man taking Terri from a nearby building. Frank opens fire and Ed arrives. Frank covers him (with a blanket) and is forced to take a hostage to counter the kidnapper's hostage. The kidnapper tries to escape and trips over Ed, and Frank captures the man. The kidnapper is revealed as the butler, Thames, who admits he kidnapped Terri for the money.
At Police Squad, Ed tells his superior that everyone on the squad helped break the case. Ed and Frank prepare to send Thames to Statesville Prison, while the killer chimpanzee gets loose.