Sadako clearly has no clue about romance (or relationships in general) so this arc will presumably teach her how that works.
After Hana leaves with Moon, Marina pushes one of her legs between Sadako's legs, pulls Sadako's thigh up at a like 140° angle while dipping her, and tries to kiss her on the lips. And in 7.5 she "accidentally" has her fingers on the side of Sadako's breast. So never mind romance, Marina goes way past just hitting on her and ventures into night club grinding territory. Sadako is so oblivious it's kind of giving me Born Sexy Yesterday vibes, or I guess the lesbian version of it.
