Contains spoilers for this episode and earlier episodes.
Dipper and Mabel want to celebrate Soos's birthday, but discover that he dreads the occasion. Their efforts to cheer him up are interrupted by Blendin Blandin, who blames the twins for the punishment he received after their earlier time-travel interference. He challenges them to Globnar, a dangerous contest whose winner receives a wish and control over the loser's fate. Trying to escape, the twins land ten years in the past. They meet the younger Soos on his twelfth birthday and discover why celebrations hurt him: his father repeatedly promises to visit, then sends another excuse. Dipper and Mabel decide that a time wish might finally give him the reunion he wanted.
The twins return to face Blendin and survive the contest's obstacles. Its final test turns out to be laser tag, giving them an unexpected advantage and the victory. Rather than punish Blendin, they restore his freedom, job and hair, admitting that they helped ruin his life. They bring the wish to Soos and explain that he can use it to see his father. Soos chooses to heal the twins' injuries and obtain an endless slice of pizza instead. Their willingness to fight through time for him has shown him who his family already is. He spends his birthday with them, while a closing glimpse of the past shows young Soos beginning his long connection with Stan and the Shack.