In the fanfiction, the kiss could be a moment of realization for both Adam and Sally. Adam might realize that his feelings for Sally are deeper than he thought, and Sally could feel the same. It could also be a moment of vulnerability. They then have to deal with the consequences in a town like Spooksville. For example, there could be a curse that is triggered by strong emotions like love, and they have to find a way to break it while also exploring their new relationship.
Well, perhaps the kiss is a turning point in their relationship. Before the kiss, they were just friends dealing with the strange happenings in Spooksville. But after it, they become closer and start to rely on each other more. They might go on adventures together to protect the town from dark forces, with their new - found bond giving them extra strength.