Taiji's normal body temperature is 38 degrees Celsius, or so he says, but Shiina thinks he's full of it. Taiji is a friend with whom Shiina can always--and does always--fight... Until Taiji unexpectedly confesses his love! Shiina begins to run a fever, but is that the only reason she's getting so hot...?
But that's just the first story.
The second it called "Solution Maze" and has a more serious feel to it.
Next is "Heaven In Jail" which is about a girl who's photo somehow ended up in a questionable magazine. Which is then found and used to blackmail her into doing homework and the like.
The third is "Winter's Aquarius" which is about a girl taking swimming lessons and it's more comedy then romance.