The story: New Orleans radio executive Brad Whitaker (Will Ferrell) tries to be a good dad to his two stepchildren but without much success. Just when he seems to draw closer to the kids, Dusty (Mark Wahlberg), the supercool biological father and ex-husband of his wife Sara (Linda Cardellini), pops ups in their lives. Brad is severely intimidated and comical rivalry ensues.

Wahlberg and Ferrell can do this cool dude-loser guy combo routine in their sleep. But to elevate this twosome to a memorable odd- couple status here, this flick needs more edge, more nuts and definitely more guts.

Their pair-up in the 2010 action- comedy The Other Guys, about Ferrell's meek cop and his hot- headed partner played by Wahlberg, was way sharper.

You wait for a hint of Ferrell wickedness or a sign of potent Wahlberg meanness to really zing us, but get a high-school comedy which has been neutered to a harmless, toothless PG13 rating.

Director and co-writer Sean Anders (Horrible Bosses 2, 2014) plays it so safe, you wonder if he attended too many parental counselling meetings himself.

The lines are drawn as clearly and starkly as Ferrell's perpetual sad-sack frown: His character, Brad, a hapless nice guy, welcomes his two stepkids' sensationally hip, occasionally shirtless biological father. Big mistake, because the formerly absent dad is back to reclaim his parental throne.

Oh, you know the mild vs wild contrast.

Brad has pieces of wood nailed pitifully to a tree in the garden; Dusty builds a happening tree house.

Brad looks for a winning jingle for his jazz radio station; Dusty nails it with his amazingly cool soul voice.

Brad tries to bond with the children with cute warm tales; Dusty bribes them with a cold 20 bucks.

From there, the script gets lazier with the usual comical set-pieces such as an extreme skateboard challenge that subsequently involves emergency CPR.

Deep down, Brad and Dusty are such tight pals that the true interloper here in this hidden bromance is Brad's wife and Dusty's ex, Sara.

The director's plan seems to be to just coast on Ferrell and Wahlberg's natural chummy chemistry, and when that slackens, bring in some help from the side.

The show picks up when Thomas Haden Church (Sideways, 2004) slides in as Brad's boss to ramble about things tangentially amusing, and Bobby Cannavale (Ant-Man, 2015) scores as an over-enthusiastic fertility expert with one hilarious scene of Wild Manhood vs Mild Manhood.

Man, that almost gets too un-wholesome.