Let's see Sami was supposed to kill EJ by setting the cabin on fire but couldn't go through with it. As she was leaving, the whole place went up in flames, and a previously unconscious EJ was calling for her to help him.
Steve decided to tell the police all he knows about EJ, but then one of EJ's men posing as a dr. put that card in his face, and he had one of his "episodes".
That girl from the island (Gabby?) put the moves on Shawn, who rebuffed her. But she had kissed him on the cheek, and Belle saw the lipstick marks

Belle was upset but later decided to trust Shawn when he said that nothing happened. Then she overheard that girl and some other guy through a bedroom door and thought that it was Shawn and the girl.
I'm sure the link that MrsMcDowell gave you will sum it up much better, but that's the gist
