Pluto

Ai-oon's identical twin Ob-oom is in a tragic accident the night of her wedding. Ob-oom survives but is left in a coma and her husband doesn't make it. Helpless to do anything for her sister, Ai-oon resolves to do her the favour she'd refused hours earlier. This leads her to a woman she could not have prepared for her, a woman she finds herself drawn to even as she questions whether she could have been involved in Ob-oom's accident.

Jan, Ob-oom's best friend, tries to discover the truth behind the accident that happened to Ob-oom and her husband. Meanwhile, Ai-oon begins to get caught up in her attraction toward May.

Ai-oon realizes how small her position is in her grandmother's heart compared to her twin, as she also has to face complicated feelings between falling in love with May and realizing that May's love isn't for her, but for Ob-oom.