When I was a kid, I devoured the Sweet Valley High series by Francine Pascal. There were plenty to read—there are 152 books in the series. Usually they followed the antics of two blonde twins, Elizabeth, the smart one, and Jessica, the popular one. The stories are usually sweet and mild, discussing the difficulties of teen dating and spats with your parents.
But for some reason, Pascal decided to take the twins on a turn for unreality and danger in nine books outside of the main series called Super Thrillers. In one book in the series called Double Jeopardy, Elizabeth witnesses and murder and the murderer tries to kill them. In another, both girls get internships at a newspaper and have to stop a bomber before he destroys the town. Good work for two girls more bubblegum than bite.