Dolly (voice of Ellen DeGeneres, Ellen DeGeneres), who suffers from short-term amnesia, once had a wonderful family. However, a series of accidents separated her from her amiable parents. Over the years, Dolly met the clownfish father and son Marlin (voice of Albert Brooks) and Nemo (voice of Hayden Rolence), and experienced an unprecedented adventure with them. In the quiet days, fragments of childhood memories suddenly broke into Dolly's mind, so she embarked on the journey to find her parents again. This time, she came to the Museum of Marine Biology and Marine Life and met Hank, an octopus who did not intend to return to the sea (voice of Ed O'Neill Ed O'Neill) and his childhood friend, the whale shark transporter (voice of Kaitlin Olson Kaitlin Olson). Following the clues in her memory, she got closer and closer to her parents. However, in the process, she was separated from Marlin and his son. The persistence in friendship and family affection makes these little guys stick to it no matter how difficult it is...