Someday, we'll know (2014)

The swimming team is deflated after its captain, Tin Heng, passed away tragically. However, a reserve of the team, Gei Yuen, works his way up in hope to represent his captain in competitions and to boost the team's morale. His mind may be focused on Tin Heng whom he idolises, but he cast his watchful and silent infatuated glances on Tsz Suen, Tin Heng's girlfriend and member of the girls' swimming team, who remains aloof and even apparently nonchalant about her boyfriend's death. Gei Yuen originally thinks Tsz Suen is dismissing her emotions to mask her sadness. However, he finds out that she is harbouring a secret...

Unfortunately the movie Someday, we'll know is not yet available on HBO Max.