This series takes place during X-Men #160, when Colossus’ little sister, Illyana, was kidnapped by the devil-stand-in Belasco, and taken to his hellish Limbo dimension.
It’s a fun story–a fantasy tale involving alternate-reality versions of X-Men.
It’s an origin story, really, for Illyana becoming Magik–foundational for subsequent issues of New Mutants.
The art on #1 is by John Buscema (yay!) but then Ron Frenz and Tom Palmer take over. They’re good, but they’re not Buscema.