The young bionic amnesiac known as Number 13 searches for answers and his creator, in a future world that's been brought to its knees by the vicious Monstrum Morbus plague. Weakened by his last explosive encounter, Number 13 is discovered by a group of curious, scavenging mutants who have banded together for survival. They dub him 'Thirteen' and invite him to join their group-and one of them knows exactly what horrible purpose he was built for!