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