Magnus Chase dies on his sixteenth birthday and wakes up in Valhalla. From there he is drawn into Norse mythology, a world of einherjar warriors, Valkyries, frost giants, and a countdown to Ragnarok that may already be unstoppable. Set in Boston and the Nine Worlds of Norse cosmology, this trilogy brings a new voice and a new mythological system into the Riordanverse. Magnus is the cousin of Annabeth Chase, which connects the series to the Greek world, but the Norse mythology operates on its own terms and the series stands alone.