Sung-cheol and Mi-sook are a couple running an interior shop. They lost their son Eunchan 6 months ago, who drowned while saving one of his friends, Ki-hyun. One day, Sungcheol witnesses Kihyun, being harassed, and decides to take the struggling boy under his wing. His wife, Mi-sook attempts to have another child through artificial insemination but fails. Despite being in despair, she finds solace in Ki-hyun who slowly becomes part of the couple’s life. But one day, Ki-hyun confesses a shocking truth behind Eunchan’s death.