Season 4

After the day the girls fighted Tess, everything turned upside down for Amy, and the others. None of the girls can remeber anything about figting Tess, only Tess seems to know whats going on and is now scared of Amy as she tries to tell her she is not a monster. However the girls meet up at the cave and suddenly everything came back to them, after Kelsey's judgement on the subject, they decided to let it be for a while. But Tess have contacted a marine biology center, meanwhile Kelsey and Amy have a fight over trusting Tess, and it ended with Amy kicking Kelsey out of her house. But after Amy finds out what Tess have been up to, she warns Brenna and the two of them call Kelsey and soon figured out a plan to get rid of any evidence.

Lot's of people have been asking questions, but you'll have to wait until Season 5 to find the Answers. :)