Reunion comedy about a nerdy but successful author, Henry (Mark Polish), who returns to suburban Sacramento to give a speech at his old high school. Once there, he finds himself falling for his former crush Scarlet (Winona Ryder) all over again. Sadly, she's still not interested. Caught in a romantic time warp, Henry's path to true love is further complicated by his crazy old principal (Chevy Chase) and the incorrigible Shasta (Hilary Duff), a sexy senior who has the serious hots for him.
After writing his book, 'How Lionel Got Me Laid', 30-something Henry McCarthy (Polish) is invited back to his former high school to make a speech, motivating the students to aim high in life.
Returning to Sacramento, he falls deeply in love - again - with his old classmate Scarlet Smith (Ryder), who was previously the most popular girl in school. Distractingly, eccentric current student Sasha O'Neil (Duff) has her eye on Henry and invites him to her senior prom. (Surprisingly, her parents don't seem to mind the huge age gap, which is a bit worrying.)
Providing laughs throughout are Henry's friends, Wino (Holloway) and Big Girl (Astin), whose song burst in a cafe immediately marks them out as completely over the top. The fun factor is boosted when Henry discovers that his old school has had to change with the gun-crazy times, everyone forced to go through security checks and hysterical 'crisis drills'.
Elsewhere, an already awkward date between Henry and Scarlet goes further downhill with the arrival of her ex-boyfriend, the resulting chase ending with Henry bring caught for speeding, But since the cop was also in his class, Henry gets off lightly twice - escaping physical headaches from the bully and legal headaches with a warning. Henry's homecoming isn't all bad luck, then.
There are some unintentional distractions, particularly during a deep conversation between Henry and Big Girl in an amusement arcade when an over-enthusiastic gamer in the background overpowers the main discussion.
In true romcom tradition, Stay Cool's plot doesn't hold many surprises (especially as any it intended were given away in the trailer). It does, however, save one revelation for the end.