When 14-year-old Leo's mom Tasha Dooley marries billionaire inventor Donald Davenport, he moves up in the world, but neither he nor his mom in their wildest dreams imagine that Leo will soon find three bionic super-powered teenagers - Adam, Bree and Chase - living within a secret lab beneath the inventor's expansive home. Now Leo has three older "siblings" to watch out for him while he introduces them to the outside world. School life and super-adventures await them all.