When Henry and his classmates find a heart-shaped box on Mr. McCarthy’s desk, Sydney wonders whether “Mr. McCarthy has a girlfriend.” Nonsense, according to Henry: “Teachers don’t have girlfriends. They never leave school.” Nevertheless, the students keep an eye on him as he chats with the playground monitor, accepts an extra tuna melt from the lunch lady and eats it with the French teacher—egad! It will surprise no one to learn that the box is for the students, but the final frame does provide a visual hint as to Mr. McCarthy’s private life. Carlson’s familiar characters provide a sweetly thought-provoking Valentine interlude for the early-elementary set. (Picture book. 5-8)