A loved-up Mitzeee and Riley prepare to go public, but a humiliated Mercedes is determined to put an end to their happiness and decides to turn the heat up on Mitzeee. Walker warns Ally to keep schtum about his past, but when a passing Lynsey witnesses it, Walker's oblivious to the fact that he's put someone else on his trail. Doug and Ste break the news of their new landlord to Amy, while a rebellious Lacey decides she's had enough of Martha's hypocrisy.