On the eve of the wedding, the bride Grace attends a bachelorette party with her best friends Harper and Claire. The next day, the two wake up in a messy hotel suite: Harper has a mysterious tattoo, Claire has pink hair and a championship gold medal, and Grace has completely disappeared. Following clues from a fake groom, tattoos, a black escape box, casino chips, a wedding ring, and torn vows, the two trace back the truth of the previous night. They gradually discover that Grace did not run away from the wedding, but rather no longer wants to be the "perfect bride" in everyone's eyes. In the end, surveillance footage proves that Grace never left the hotel—she hid inside the black box for a ten-second prank, but was pushed under the bed along with the box by her drunken best friends, and slept straight through to the wedding day. With only twenty minutes left before the ceremony, the three rush clumsily into the wedding venue and finally complete the most imperfect yet most real wedding.
