The two were very close when they were young, but now their relationship has become so distant that they seem like complete strangers.
However, whenever they are alone together, Haruki becomes affectionate and clingy again, just like in the old days. Taichi, meanwhile, continues to be suspicious of this behaviour.
Eventually, Taichi reaches the limit of his patience and tries to push Haruki away, but... that's the basic premise of the story.