Caldecott Medalist, National Book Award winner, and New York Times bestselling creator Dan Santat returns to Sidekicks with a brand-new adventure in this second series installment!Suit up for high-octane action and laughs! There's trouble at the Society of Superheroes! Captain Amazing, the longtime hero of Metro City, has retired, and he's enjoying a much-needed vacation at the World's Biggest Ball of Yarn.But while he's away, there's trouble at home! A massive data breech disrupts the Society of Superheroes, and a flash drive containing sensitive information about Captain Amazing and other heroes winds up in reckless hands.Meanwhile, an unannounced visitor named Whipley arrives at the captain's house, and his pet sidekicks -- Manny, Roscoe, and Fluffy -- are skeptical of the stranger's intentions.The only sidekick excited by the visit is Shifty. Could Whipley be Shifty's loving, long-lost brother as he claims? Or is he framing the sidekicks for his own personal gain and vengeance?