The second Metroid game picks up soon after the first, with Samus having defeated the Mother Brain on Zebes and heading for the Metroids' homeworld of SR388. Deep in the bowels of this unstable planet, Samus finds lava, earthquakes, and more evolved species of Metroids, until finally coming face-to-face with the Queen Metroid herself to eradicate the species for good, with the exception of a single Metroid hatchling...