The Metamorph Files Book 3: Shadows of the Agent. The Metamorph Files, #3

In the thrilling third book of The Metamorph Files, the Junkyard Detectives Club faces their greatest challenge yet. One year after stopping the original Project Metamorph threat, twelve-year-old Alexa and her friends discover that the dangerous resequencing agent is back - and this time it's about to be released across the entire county. With new allies, growing powers, and the added complications of middle school life and puberty, Alexa must lead the team in a race against time.
As they investigate hidden launch sites, uncover betrayals, and battle shadowy enemies, the friends learn that real strength comes from sticking together through every challenge - both the ones with glowing energy and the ones happening inside themselves. Full of heart-pounding action, unbreakable friendship, and courageous growth, Shadows of the Agent is a story about finding your power while navigating the biggest changes of your life.