Naoto is given one day to reunite with Mio, his deceased lover, through an AI reconstructed from her brain data. Installed on his smartphone, Mio speaks with the same voice, memories, and mannerisms she once had—yet her existence is limited to just 24 hours. As they spend the day together in Tokyo, visiting familiar places, meeting Mio’s mother, and preparing for Naoto’s art exhibition, their conversations oscillate between the ordinary and the profound. While Naoto struggles between holding on to the past and continuing to live in the present, the countdown to their inevitable farewell draws closer.