Chien-yu and Chih-pang are best friends, but they face challenges when Chih-pang unexpectedly vanishes on his 16th birthday. Upon Chih-pang’s return, Chien-yu discovers he’s the only one who can see him. Amid these unusual circumstances, the two seize the opportunity to reveal the secrets they’ve been keeping in their hearts, embarking on a journey of self-discovery.