Thread:Xesc13primero/@comment-26113939-20161225233242/@comment-26113939-20161228141825

Basically Sakutaro and Yuki died two years prior, and a lot of episode 3 was to trick you into thinking YukiTaro wasn't pre-established in AiColor. Josh reveals the entire "accident" was a facade set up by a "murderer".

Tl;dr: Yuki and Sakutaro have been ghosts since episode 1, and not even Kou or Dia noticed, since the Tomoe and Sakurai families did all they could to cover it up.