牯岭街杀人少年Keith, a defeated adult store owner, falls for a younger woman who visits his shop looking for a gift. When their relationship turns physical, Keith’s failure to perform leads him to a strange doctor who offers hope in the form of a new experimental drug. The experience gives Keith much more than renewed manhood. It also provides a glimpse into a parallel universe where he is not only the singer of the band OFF!, but also the target of an evil alien species that will stop at nothing to prevent the group from making a new album which holds the key to an awakening of human consciousness.