When his newly pregnant girlfriend, Emma (Cobie Smulders), decides she's had enough of his failures, David hits his lowest ebb.
But there is lower to come when a lawyer informs him that his deposits at a sperm bank 20 years earlier had produced 533 children and a group of them was fighting to discover who their real father was.
David is floored by this news and the way his life is unravelling.
But he had promised Emma he was going to do something about his life and his new offspring offer that opportunity.
Without revealing himself, David starts tracking down the "children" and doing his best to get to know them or just help them out a bit.
This new role sits beautifully with him and he grows to love the way his life has developed.
But the impending court case by 142 of his children seeking to identify their biological father means his anonymity may be taken away from him and he has some big decisions to make.
With the dubious assistance of his lawyer mate Brett (Chris Pratt), David works through the implications of revealing himself as the highly fertile Starbuck.
Although this isn't Vaughn's funniest movie, there is still plenty to like about Delivery Man and there are lots of laughs on offer.
Watch the trailer here: