Trama

The search for a yacht ends up splitting Charlie's loyalties when two agencies ask for his help.

A junior high school class is on an oceanography field trip. They release a catch from a net, and find a body in a wetsuit among the fish. FBI is called in; there is a bullet hole in the wetsuit.

The dead man is a navy diver who had fallen on hard times and was working for a marine salvage company. A sixty-foot yacht, the Cheetah, had just sunk and many salvage companies are looking for it. Charlie had consulted in the design of the yacht. The FBI goes to investigate the salvage company and finds a bloodstain on their barge, along with a picture of the missing boat. Megan talks to the owner of the Cheetah. He thinks it sank because of a design flaw in the boat. The boat captain, Reed Sarasin, is missing as well and presumed drowned. Agent Warner appears.

As Charlie tries to understand the yacht's design flaw, Millie comes in, looking for help in playing chess against Charlie's father. She has experience with yachts and tells him that he needs to account for the pressure of the water against the boat.

The blood on the barge is identified as being from the diver and also the owners of the salvage operation as well, the Morris brothers. Charlie tries to calculate where the barge might have gone, and realizes that it was never more than ten miles from shore.

Two men comes to visit Charlie in his office. They are NSA and want Charlie to help find the Cheetah. He realizes that rather than sinking straight down, it would have glided through the water and ended up far from the sinking site. He tells the men he can calculate the likely location of the yacht. They tell him not to tell anyone that he's working on it.

The diver had been weighted down after being thrown overboard but the rope had come loose. The FBI theorizes the Morrises will be found at the location of the barge, and Don goes to ask Charlie if he's made progress on that. Charlie tells him he's back-burnered the barge problem but he can't say why. When he does calculate it, they send a sub out and find the bodies, and also the Cheetah, many miles away from where it was supposed to have sunk. How did the Morrisses know where it sank?

The NSA men accuse Charlie of misleading them about the location of the yacht. Don intervenes to find out the issue, and the men reveal that they are chasing terrorists. They think the yacht was actually smuggling something but they don't know what. The FBI theorizes that Reed Sarasin navigated the yacht to shallow water before sinking it in order that he could recover the smuggled item.

Charlie notices that the yacht slowed down on its trip after leaving Singapore. NSA reveals that material for rocket guidance systems had gone missing, and Charlie confirms the weight matches.

They bring in Sarasin's wife. She identifies a boat he may be hiding on. They visit the boat, which is clearly occupied but no one is there, until they realize he has gone over the side and hidden under the water.

Saracen denies any involvement other than showing the Morrises where the boat was. He tells them that they were waiting for missiles and haven't left the LA area.

Charlie suggests using satellite data to find the truck. He applies an algorithm to automatically search the images, and finds a likely target. FBI raids the location and a gunfight ensues, and a suspect is captured and the guidance systems recovered.

Millie beats Mr. Epps at chess, and then challenges them all to poker.