Lakesider: Above and Below

Working class weeb Knox's life is forever disturbed after a cute fish girl saves him from drowning himself by accident, introducing him to a strange sunken town hidden beneath the lake. What has been seen can never be un-seen, and the effects of this inexplicable meeting of underwater fantasy and reality continue to ripple throughout his day-to-day life. Will this lead to a happily ever after, or will something far more sinister emerge from just below the surface...?

[From Steam]