The episode opens at the Krusty Krab with SpongeBob inside a curtain with a lady who turns out to be a nurse. She tells SpongeBob to stop moving, but he tells her that he has never had a checkup before. After she passes him, she checks Squidward. SpongeBob tells Mr. Krabs not to be scared, but Krabs still is despite what the nurse said. Squidward then screams at the nurse when he is forced to pee. She looks at him, but he asks for privacy. She passes Squidward and then calls Mr. Krabs. Krabs runs away and the nurse tells Squidward and SpongeBob that if they don't check Mr. Krabs, the Krusty Krab will close. SpongeBob comes up with an idea. He tells the nurse that he and Squidward will finish his checkup themselves during the weekend. The nurse approves and leaves.
As a first attempt, SpongeBob and Squidward begin their quest by hiding in a box that says "Free Money Inside." Krabs, who can't resist, tries to move his hand in there. As Squidward and SpongeBob's first job is to pinch Mr. Krabs, they do so, crushing and breaking his claws. They then disguise as employees at a shop to fool Mr. Krabs into taking the reflexes part of the test. Krabs leaves in anger when he finds out that the "employees" are abusing him rather than giving him the correct suit. SpongeBob then opens a photo booth to take an X-ray of Mr. Krabs. When Krabs enters, Squidward asks about how many X-rays he took and SpongeBob tells him 25,000 but Squidward says the list only had to do one. Mr. Krabs comes out all mutated and walks away.
As Mr. Krabs is complaining about his day. SpongeBob, unknown to Krabs, comes out of a massage parlor and asks if he wants a massage. Krabs agrees and they go inside. SpongeBob sets a trap which throws Mr. Krabs in the freezer. Squidward then tells SpongeBob that he had to measure Mr. Krabs' cold temperature to compare if it is the same to the water around him, not freeze him to death.
Mr. Krabs comes out of the freezer and SpongeBob tells him that he can work out to pass his physical throughout the weekend. SpongeBob then breaks the ice with a mallet, but Mr. Krabs' shell cracks and his teeth fall out. He then starts crying. During the weekend, Mr. Krabs is unable to do any of the workouts, which results in cracking his shell again. SpongeBob and Squidward fear that the nurse will close down the Krusty Krab for sure now that Mr. Krabs looks more terrible than before. However, Krabs tells them that he has a plan.
The nurse comes back and tells "Mr. Krabs" that he passed and she adds that he also looks handsome. She then leaves stating she will be back next year. Larry, who was the one impersonating Mr. Krabs, says he wants money because he helped the real Krabs, but Mr. Krabs quickly escapes as the episode ends.