Lee Kyung-sook spent her entire life sacrificing everything for her family.She was the definition of devotion, yet her son, Seo Min-wook, could never bring himself to say a simple “thank you.”​After her passing away, Min-wook lives a life drowned in regret…until an unbelievable miracle occurs.He regresses back to the very day his family’s tragedy began, waking up in the body of his uncle, Lee Dong-ho.