An improbable jumble of bumbling romance, frenetic bloodshed, giddy slapstick, cockeyed cannabis jokes, and a pair of half-wasted stoners as crime-fighting heroes, "Pineapple Express" is the unlikeliest comedy of the summer. It's also going to be one of the best-loved.

Action comedies usually fly by at a manic, car-smashing pace, but this shaggy-dog story (by star Seth Rogen and his "Superbad" writing partner Evan Goldberg) ambles from one absurd turn of affairs to the next while paying plenty of attention to giggly character notes. Its buddy-buddy elements are the emotional bedrock supporting the film's considerable action shenanigans. This time the stakes aren't financial, but emotional. How the characters feel about each other at the fadeout matters more than who makes off with a bundle of loot.

Rogen brings his teddy bear amiability to the role of Dale Denton, a Los Angeles legal-process server who ambles through his humdrum workday in a cumulus cloud of cannabis.

"You're a servant?" marvels his dope dealer, Saul Silver (James Franco, blissfully zonked in every scene). "Like a chauffeur? A butler?" Franco's performance is inspired. You can almost see empty thought balloons floating over his character's head.

Saul, who conducts his business behind a multi-locked door, is a rather isolated dude, just bright enough to suspect that people like him for the mind-blowing product he sells rather than for himself. He invites the likable Dale to hang around, hoping to kindle a friendship over a cross-shaped superjoint, though Dale would rather finish his deliveries and catch up with his impossibly hot 18-year-old girlfriend.

His next stop turns Dale into a mob-murder witness and a man on the run. The killer finds Dale's castoff joint, traces the uniquely potent weed back to Saul, and comes after the duo with a cadre of comically menacing goons.

What follows is a succession of chases as the fugitives make their escape with the spur-of-the-moment randomness of the truly stoned. While their survival is the dramatic mainspring of the story, the emotional bedrock is how the small, quirky details of their personalities mesh to launch an unexpected friendship. Saul's puppy-dog neediness whittles away at Dale's kvetchy defenses, and director David Gordon Green's delight at the rapport between his two stars is contagious. The bulky Rogen and slender Franco have an offbeat chemistry that's utterly engaging.

Be aware, though, that this is one unapologetically violent movie. The R-rated action is pitched at a level of fun, alarming sadism -- the ridiculously cruel bloodshed intends to thrill, and it succeeds, a running parody of sledgehammer crime thrillers. Rogen's Dale serves as a bemused Greek chorus, commenting on the action as it erupts all around him.

The destruction escalates from trashing the apartment of a boastful drug connection (Danny McBride, the film's comedic ace in the hole) to a climax as kaboom-filled as any breakneck summer multiplex release. Green twists the tone expertly, however; even the most bruising fight sequences feel like explosions of high spirits. The bicker-and-bond allegiance that emerges between Rogen, Franco and McBride may be illogical, but it's a treat nevertheless. It's a rare thriller that ends with the idea that intimacy is life's greatest treasure, but this one does, and it's likely to put a lump in your throat even as you chuckle.

Colin Covert • 612-673-7186