You Nai Nam (You ในน้ำ - You, in water) // WilliamEst

When William, an 18th-century Siamese nobleman, slips in his bath and hits his head, he wakes up not in his familiar palace, but in a strange land of noise, glass towers, and tiny glowing boxes-modern-day Bangkok.

Found nearly unconscious in a deserted sports center pool, he's rescued by Est, a once-celebrated swimmer turned recluse.

Est, recovering from a career-ending shoulder injury and deep depression, isn't exactly thrilled when this strange, dramatic man starts calling him "commoner" and treating showerheads like sacred artifacts.
But Est's coach, who is also William's lookalike, believes the nobleman's behavior is a delusion-and sends both men to a psychiatric facility for treatment.

Between group therapy, rooftop escapes, and midnight pool visits, Est begins to find unexpected joy in William's presence, and William begins to understand the language of the modern heart. But time is fragile.
And love? Even more so.