A lot. The kid is a kind of an OP scavenger / hunter on this craphole planet and the girl is from another world. He finds her ship / pod (I don't quite recall) where she was in hibernation sleep. He gets her out of hibernation sleep but she doesn't wake up immediately. He has a big time booby fetish due to unresolved abandonment issues, so he's cuddling up to those while she sleeps because he doesn't know what else to do. On his forehead is the kana for "baka" (idiot) which was written there by a friend of his. Because he was feeling vindictive about that friend, he wrote it on this sleeping girl's forehead as well just to kind of make a point. She wakes up, finds him cuddling her boobies, gets pissed, pulls out her magical fighting devices, they fight, yadda yadda seen in the WEBM. After the last bit, she realizes he wrote "baka" on her forehead, which matches the "baka' on his forehead. On her planet, and in her society, when you share the same facial markings, it means you're married. So not long after this (and after it doesn't rub off), she basically becomes his wife.