The Trouble with Girls: Night of the Lizard #1

Lester just wants to be left alone to finish reading The Adventures of Tom Sawyer, but he keeps being attacked by various enemies and pursued by desperate, beautiful women. He rejects an offer to work for the secret agency called MUM (Masterful Undercover Manipulation), but both his father and Maxi Scoops believe that he should do it to give a nobler purpose to his life. Finally he relents and goes to meet with the head of MUM (who turns out to be an old woman called Mum), and she tells him that he'll be facing off once more against the Lizard Lady.