Jake's retirement consists of beer, brats, watching beach bunnies pass by his patio deck and trading wisecracks with Arlo, his pet chameleon. OK, so it's a one-sided exchange, Jake doesn't mind.
That all changes when they are conscripted into service for the Federation of Thirteen Galaxies. (Twelve actually. They lost one of the Galaxies but it's too expensive to change all the letterhead, so there you go.)
Book One, 'Arlo and Jake Enlist', follows the adventures of our dippy duo as they are snapped off the beach and into service as ABSs (Able Bodied Spacemen).