Once in a Lifetime is set in Mistbury, a town that appears entirely normal on the surface — an impression that does not survive contact with what lives underneath it. The protagonist shares what seems like an ordinary life with their family until events escalate beyond anything ordinary: breaking into a prison, exploring forbidden mansions, crossing the world, and navigating a web of conspiracies thick with strange and dangerous characters.
Beneath all of it looms Astaroth, whose rise to power would be catastrophic for everyone. The protagonist is the only one in a position to stop it.