Tom Pearson is a 15-year-old techno-geek and the main protagonist in Aliens in the Attic. He is the brother of Hannah and Bethany Pearson, cousin of Jake Pearson and the son of Stuart and Nina Pearson.
Unlike his parents, Tom is not excited about going on a family fishing vacation and believes that "There should be a discount for getting booked at the most boring spot in the whole country." He used to be a straight-A student, but has recently decided to get bad grades on purpose so he will be thought of as cool, which does not please his dad. The family vacation does not start out well for Tom; he gets stuck in the middle seat on the car ride to the lake house and Beth's annoying boyfriend Ricky shows up without warning. When the aliens arrive, Tom uses his geeky skills to fight them. His smart ideas pay off, and Art, Lee, and Hannah eventually grow to recognize him as their leader. Tom eventually learns that there are advantages to being smart and tells his dad that he was right all along and Tom was wrong. He also grows closer to his siblings, and even uses Ricky's mind-control device to help Bethany ruin Ricky's relationship with his new girlfriend.