They had been best friends since they were in kindergarten, but they'd never had an entire summer together. Willow's parents had been anxious to leave Sunnydale whenever they could, meaning only when Willow was out of school, and Xander's family had sporadic road trips to rare landmarks that would have frightened the most stalwart of Americana enthusiasts.
This summer, though, Willow's parents had decided she was old enough to stay behind. Xander hadn't been on one of the dreaded family road trips in about four years, pleading summer sports commitments that he didn't actually have, and his parents didn't really care anyway.
So they patrolled together at night, and hung out in movie theaters and ice cream parlors in the day to escape the southern California heat. They had marathon sessions of Risk and Xander pretended to let Willow win Trivial Pursuit (the fact was, she walloped his ass). At one point, they played Magic, until Willow got so critical of the terminology in the game that they had to give it up, for Xander's sanity.
And once or twice, they almost kissed.
Which Willow remembered even into the winter, and beyond that, and to which she held on, tight, when she found out about Xander and Cordelia.
Which Xander remembered, when he had a rare moment alone with Willow after Buffy came back, but to which he attached no immediate significance.
There was never another summer like it.