Denver has been searching for a quarterback for four years and the answer, at least for now, is Joe Flacco. He played 11 years in Baltimore, leading them to the playoffs multiple times, including one Super Bowl victory (more on that in a moment). He was officially traded to the Broncos organization in March and on Monday night, No. 5 will take snaps for the Broncos in Oakland against the Raiders. For some Broncos fans, it will be a bit jarring.

Flacco was never despised in Broncos Country as much as Tom Brady or Philip Rivers, but he did break fans’ hearts when he stole a playoff win from the Broncos in the 2012 season, ending Peyton Manning’s first shot at a Super Bowl in Denver.

For those of you who remember the play, this will be painful. If you don’t, here’s a quick return to the scene of Flacco’s villainy against the Broncos:

Manning and the Broncos hosted Flacco and the Baltimore Ravens in a 2012 AFC Divisional Round playoff game. The Broncos entered the matchup on an 11-game winning streak and were expected to win. Temperatures fell into the single digits.

The Ravens were down seven points with under a minute remaining when Flacco heaved the ball the length of the field toward teammate Jacoby Jones. Broncos safety Rahim Moore leaped in front of Jones to cut off the throw. Moore missed. Jones caught the ball and ran for a touchdown.

The Ravens won the game in double overtime as Denver fans sat, stunned in a subzero windchill. Flacco led the Ravens to a Super Bowl XLVII victory over the San Francisco 49ers (he was Super Bowl MVP) and he continued to be a fine quarterback moving forward. Last season, Baltimore replaced him at the position and the Broncos traded a fourth-round pick for Flacco in the offseason.

It’s tough to erase that Flacco play from memory, so don’t be surprised if some Denver fans fret about that (or his age). Still, in training camp, he looked miles ahead of any quarterback the Broncos have had since Peyton Manning (another foe-turned-friend).

Broncos general manager, John Elway, was happy to add Flacco to the team because of his competency. Flacco can handle the grind of an NFL season and make throws—some of them very long, game-winning throws—that put his team in a position to win.

As a bonus, Flacco’s chemistry with Emmanuel Sanders in training camp was encouraging. Sanders went down last season with an Achilles injury but looks healed and ready to play. Flacco also has Phillip Lindsay’s running game at his disposal. Other than that, the Broncos have a lot of guys hoping to prove themselves, including Royce Freeman, Courtland Sutton and DaeSean Hamilton. But with so many unknowns, Flacco has a lot to carry—including the weight of a fan base that is tired of losing.

The worst-case scenario would be more of the same this season. (Four seasons ago, the Broncos won the Super Bowl. This year, they’re projected to miss the playoffs.) If that happens, would fans turn against Flacco? Would Elway have to try—yet again—to find his quarterback?

If Flacco succeeds in Denver, his story is intriguing and the best-case scenario will be that Flacco’s long Hail Mary all of those years ago is the start of a story that ends in Broncos playoff wins.