Unfortunately for the Welsh club's A-list co-owners Ryan Reynolds and Rob McElhenney, it wasn't to be a happy ending as the Robins saw their promotion hopes end following a nine-goal thriller at the Racehorse Ground.
It was Wrexham who took the lead after just 13 minutes through Paul Mullin, before John McAtee levelled the match just two minutes later for the Mariners.
After your typical first 45 minutes, Luke Waterfall put Grimsby ahead at the start of the second-half.
But for the 9,734 fans in Wrexham, and all of those watching it home, no spoiler could have predicted what would happen next.
A double from Ben Tozer and Mullin midway through the second-half put Wrexham back in front at 3-2… before the scoreline swung again as Ryan Taylor and Mani Dieseruvwe fired home to make it 4-3 to Grimsby with 12 minutes left.
Spurred on by their home fans, Wrexham weren't done yet as Jordan Davies headed home from a corner to draw the semi-final clash level and take it to extra-time.
With no sequel to this blockbuster, fans knew that a winner would be needed on the day, and what followed was a nervy period of extra-time that could clearly have gone either way.
However in the most dramatic fashion, it was the visitors Grimsby who progressed to the National League play-off final with a 119th-minute winner from Waterfall.
As a result, the Mariners will face Solihull Moors or Chesterfield in the final at West Ham's London Stadium on Sunday, 5 June.
The winner of that contest will secure promotion back to the EFL, in League Two.
For Wrexham and their new celebrity owners, the focus will now turn to next season as they look move the club up the football pyramid.
Reynolds and McElleney are very much used to happy endings, but like any big screen flick, you have to experience the fall to rise again - something that they'll be determined to achieve at Wrexham.