After the events of the second film, Larry and his now teenage son have to travel to London after the tablet of Ahkmenrah starts to corrode and causes the artifacts to act weird and cause chaos when they come to life. They are soon told by Cecil, a archaeologist who discovered the tablet back in 1938, that the tablet's magic will soon run out and everyone will become lifeless once the magic goes away. Cecil says that the only thing to stop the magic from draining away will be to restore the tablet to the tomb it was taken from. The fight is soon on top put the tablet back and stop the effort by Lancelot, the museum's newest exhibit, from destroying the tablet.