Sylvie and Carl have been friends since they were tiny children. They've always played together, eaten meals with each other's families, called each other boyfriend and girlfriend...and deep down, Sylvie has always believed that they'll end up married to each other. They even have a magical fantasy world that belongs to them alone, as does the Glass Hut where it's all created, at the bottom of Carl's garden.
But as they become teenagers, things begin to change. They go to different schools and have different friends. Sylvie still wishes she could spend all her time with Carl. But Carl has a new friend, Paul, who is taking all his attention. Carl seems much less happy to be called Sylvie's boyfriend and in a game of spin the bottle, he avoids kissing her. Sylvie can tell his feelings have changed and that her plans for the future may be affected. But can she guess at the true reasons behind it all?