Ceres, Celestial Legend V.6: Double

Toya receives a jolt to the head and suddenly remembers everything about his past - a simple life with a girlfriend who is a dead ringer for Aya! Regaining his memory has somehow caused Toya to forget everything that's happened in the past year, including his memory of Aya. If Aya has a double, does that mean that there's also another Ceres?

Episode Titles:
16. Another Ceres
17. Bewitching Affection
18. Fleeting Happiness