From this episode, it's quite clear that Lucy is responsible for the holes in Kohta's memories. They had a run in eight years ago which ended in Kohta's father and sister getting killed, and Kohta himself becoming traumatized to the point of repressing the memories.
Where the writers plan to go with this is unclear, as with Kohta and Yuka's relationship. They're cousins. What is it about horror anime and including incest? From where I stand there doesn't seem to be a real story line at all, just a retelling of events which took place in years past. I give the episode 9/10, if for nothing more than Nana came back for no apparent reason.





