As Supergirl escorts a dangerous shipment of Kryptonite to S.T.A.R. Labs, Metallo attacks the armoured truck. The superpowered cyborg is bent on claiming the radioactive rock for himself. When the Girl of Steel intercepts the man of metal, a brawl for the ages spills into the streets of Metropolis. Can Supergirl keep the Kryptonite out of Metallo's clutches and save the city from destruction at the same time? Find out in this action-packed chapter book for DC Super Hero fans!