Slavni štirinogi kosmatinec se vrača kot mladič in tokrat tudi govori. "Najslabši pes na svetu" ima živahen glas in nič manj igriv značaj. S prijateljem Bodijem poskrbita za zmedo na pasjem tekmovanju, pri katerem se Marley izkaže kot izjemno prebrisana žival. Zlahka užene dobermane in ovčarje, medtem ko vnovič greje srca na svojevrsten, prisrčen način.
Fatherless Bodi Grogan dreams of his own puppy, but the best he can get from his workaholic ma Carol is minding friends' naughty pup Marley while he's dumped for the summer with grandpa Fred, a rather strict US Marines veteran. If they do really well a permanent dog is on the cards, so Brdoy resolves to j-enter the local puppy obedience show, which only allows teams, so he recruits Fred's friendly neighbor Crouch's sibling pups Moose and Fuchsia. They're up against ruthless title defender Hans Von Weiselberger, whose henchman help him cheat and terrorize their own Dobermann pups, but grandpa's military experience comes in handy once he sides with team Bodi.