Night at the Museum begins with Larry Daley (Ben Stiller), who jumps from job-to-job, earning just enough to get by. His son lives with his ex-wife and her successful husband, making him feel like an even bigger failure than his job hopping does. Larry thinks of himself as an inventor who is great a coming up with ideas for inventions but who doesn't have the fortune it takes to make his ideas into reality.
He has just lost his job and has to a new apartment that is much cheaper. To make matters worse, his wife is tire of seeing him going from job to job and says she is going to quit letting Larry see his son until he has a steady paying job. He finds a job as a night watchman a the museum for natural history, hence the title Night at the Museum, and he heads down to the museum for the sake of his son.
Now It Gets Interesting
When he arrives he is directed to the senior watchman to show him around the museum and to explain his job. The watchman then leaves to go to his retirement party, leaving Larry alone on his first night on the job.
Everything is going fine for Larry until the sunsets. While dozing at his desk, he is suddenly awaken when the giant Tyrannosaurus Rex model begins to move around. Things take a turn for the worse as the whole museum comes alive with exhibits. Fortunately for Larry, the helpful Teddy Roosevelt, played by Robin Williams, explains that this is nothing new to the museum. It happens every night due to a magical Egyptian artifact. He tells him that nothing must leave the museum or the escaping exhibits will turn to dust when the sun rises.
Teddy offers some advice but feels that Larry should figure most things out for himself. Larry makes his way through the night only to be yelled at the next morning by the snobbish museum overseer for the carnage left in the wake of the many historical figures. Larry does not like the ideal of doing the job every night, picking up after 2 millions years worth of chaotic exhibits, but he also finds the thought of working in a place history truly comes alive each night.