Fifty-four year old Kostis (Makis Papadimitriou, CHEVALIER) arrives on a Greek island in the chilly off-season to take up a private practice among the roughly eight hundred locals (who all know each other by first name). He is content in his solitude, with only a minimum of forwardness from the curious locals, but cannot help but look forward to tourist season when the island comes alive. As the summer comes and the island fills with pleasure-loving foreign tourists, Kostis maintains his solitary nature until he meets wildchild Anna (Elli Tringou) and her friends who conga line into his exam room for treatment. Reluctantly stepping out onto the beaches among nudists with modest trunks and a mask of sunscreen, Kostis reluctantly joins Anna and her friends, entranced by her and managing to shed his inhibitions with alcohol and dancing. As the season continues, Kostis preoccupation with partying takes precedence over his practice. When he discovers that Anna is not even interested in so much as a fling, Kostis goes from clingy to obsessive, determined to possess her even without her consent.

A character study of loneliness and unmet expectations, SUNTAN finds middle-aged Kostis desperate to be someone else and not realizing how ridiculous he looks; which would not matter if he actually did not care about appearances and had he possessed an ounce of the joie de vivre of the similarly middle-aged fisherman Takis (Yannis Tsortekis) for whom the tourist season brings the promise of pussy and lots of it. His body issues exacerbated amidst so much firm, bare flesh, Kostis soon also feels professionally and personally inadequate when he runs into a former classmate (Syllas Tzoumerkas) who is not only fitter but also a successful plastic surgeon with a family with a summer place on the island. For Anna and her friends, he becomes the old guy that buys them beer (although they are all of age), and when they take off for a short time to another island without telling him, Kostis becomes depressed and gets drunk as soon as he shuts up his practice every day at three (refusing even five minutes for a last patient). Intensely searching their haunts on the island for them, Kostis certainly looks the part of a creepy stalker (not so much out of place for his age and weight as his dour expression), and the film remains largely ambiguous as to whether Anna's male friends are mocking him. While the film does ultimately take a dark turn that in which Kostis realizes that he has become as pathetic as he looks to others.