Following a prelude to the number one best-selling series in Japan, the story takes place in a humanity that has learned to live quietly behind tall walls, protected from the giant Titans.

However, when a cult that worships the Titans opens one of the gates, a Titan causes chaos by devouring its followers. After the destruction, two young members of the Survey Corps are shocked when they discover the half-buried body of a pregnant woman – with her baby still alive inside her!

What will be the fate of this "child of the Titans"? And how will humanity manage the threat of the Titans?