Spring festivities! Staying up all night in the summer! Even a Killer T Cell, the cool-headed professional hitman, wouldn't say no to these seasonal pleasures☆ However, the time when the seasons change is also a dangerous time for the body! Even cells that are supposed to be allies to Squad Leader just keep causing trouble and throwing the cells' workplace into chaos! Can Squad Leader overcome this ordeal and enjoy his days off...?! Every chapter is a standalone story, so you can just start reading from this volume. You'll find yourself laughing your head off as you read this hilarious spin-off of the popular Cells at Work! series☆