Two loving middle aged couples get caught in a series of marital misadventures over reasons of fidelity.

An American businessman visiting Nagoya, Japan, meets a woman in a hotel bar. Returning to her room, 3 ninjas kill her and wound him, but he sees the ninja boss' face. Now, he's the prime target of a dangerous ninja cult.

When their closest friend April O'Neil discovers an ancient scepter with magical powers, the turtles must cow-a-bunga their way back to 17th century Japan to rescue her from the evil clutches of Lord Norinaga.

Romance and adventure happen during the America's Cup series of yachting races.