Okay listen. Harry and Draco are 23 and each get summoned to the Unspeakables, are surprised to see the other one there. They find out that they are needed in the first war and are being asked to time travel to 1980. They're like, uhhhh wtf no, the war is over. And the Unspeakables are like, well it has to be you, because you both look like your fathers and we need your blood/magic signature in order to impersonate your fathers and save the world. Also, you already did it. So we know you're going to do it. So they reluctantly go and are stuffed into a muggle hotel in 1980 and keep finding out more about what they're needed for in the war but in between, they're stuck in this hotel room watching Dallas and pretending they know how to drive the 1979 Ford Cortina the Unspeakables gave them. They end up hanging out with the first OotP, specifically Sirius, Dorcas, and the Longbottoms. At first Draco is pretending he hates Dallas but he is hooked almost immediately and needs to know who killed J.R.?! Also Sirius is a terrible influence and they definitely end up all getting high together. AND ALSO SO MANY DADDY ISSUES