Love this movie so much its so pretty the animation, the storyline, the romance is perfect. but yea, don't expect a happy situations troughout the whole movie cus theres somehow an expected scene (you know.. a lil bit of angst). And don,t fetishize the relationship between them, their story is just very pure, no need to watch it just for the 3 minutes sex scene. Watch the whole movie, trust me its worth it!
Also at first im kinda shocked that the black haired boy was to one stick it in but if u wanna know the answer its on the sequel, its called harukaze no etranger. Watch the whole thing, the plot is very good!