Scheana throws a costume party for her birthday, but drama ensues when Kristen arrives, in the Season 4 premiere. Also: Lisa vows to take the restaurant to new heights; James' behavior jeopardizes his DJ career; and Schwartz realizes he's ready to commit to Katie.

When Lisa Vanderpump brings new blood to the shark-infested waters of SUR, Katie and Scheana quickly teach new girl Lala that there's no such thing as a secret at Lisa's restaurant. Rumors spread that James was unfaithful to Kristen, and Kristen must make a tough choice about who to believe. Jax imports a new girlfriend from Kentucky and Scheana continues to feel the heat from Ariana over her friendship with Kristen.

When Scheana and Katie bust Lala for lying about a modeling job in Italy, Lisa Vanderpump turns the table on them for picking on the new girl. Scheana worries her marriage may be in danger when it's revealed that her husband has been keeping secrets. Tom and Ariana try "adulting," Jax and James compete for Lala's affection and Tom Schwartz makes a big step towards committing to Katie.

Lisa Vanderpump and the SUR crew force Scheana to reassess her marriage now that Shay's secret life is out in the open. Jax campaigns to get his new flame a job at SUR, even while things heat up between him and Lala. Sandoval and Schwartz pitch Lisa a business plan. Kristen and James seek couple’s therapy.

Convinced Kristen is cheating on him, James hooks up with Lala; Lisa teaches her staff about fine wine; Jax schemes to attract Lala away from James and recruits Kristen to help him.

Lisa throws two huge parties for Gay Pride; James flaunts fresh love bites, and everyone wants to know who was responsible; Tom Sandoval and Tom Schwartz kick-start Shay's makeover; Jax seizes an opportunity to move in on Lala.

Lisa treats a group of underprivileged kids to the full SUR experience, including a serving of bad behavior from her staff. Jax stands up for Kristen when her break up with James turns ugly. Ariana's mood sours when Sandoval contemplates going to Vegas without her, Schwartz and Sandoval fail to impress with their business plan, and Jax asks Brittany to move in with him.

Lisa advises the women to get back at their boyfriends for going to Las Vegas, so Lala, Katie and Ariana kiss and make up at Scheana's sleepover; Jax, Schwartz and Sandoval strive to remain loyal to their girlfriends while in Sin City.

Sandoval and Schwartz learn that not all that happens in Vegas stays in Vegas when they surprise their girlfriends with shocking news; Kristen returns to SUR, but Ariana is not ready to forgive; Tom Sandoval and Ariana take the stage at the Improv.

Tom Schwartz finally mans up and plans to get down on one knee for Katie, but Lisa Vanderpump worries that his complicated proposal scheme will end in disaster. Brittany moving in with Jax doesn't stop him from moving in on Lala. Ariana's attitude drives Scheana and Katie closer to Kristen, Sandoval tries to correct a huge mistake, and Kristen and James get left out in the cold when the SUR crew plans a tropical vacation.

Lisa Vanderpump holds Stassi at arm's length; Scheana and Ariana realize their friendship is damaged; James schemes to get an invitation to Hawaii with the others; Katie shows off her engagement ring at SUR; Faith and Lala go skinny-dipping.

The gang heads to Hawaii to celebrate Jax and Tom's birthdays; Tom learns Scheana sent derogatory text messages about him to Ariana's mother; Katie lashes out when Lala swims naked in front of Schwartz.

When Stassi visits Kristen, she reveals the truth about her sex tape; Arian refuses to accept Scheana's apologies; Lala kicks James out of bed; Jax winds up in jail.

Accused of shoplifting, Jax must answer to the law, to his girlfriend and to Lisa Vanderpump; Stassi returns to SUR to repay Lisa for keeping the sex tape from leaking; James and Lala cannot keep their hands off each other during a photo shoot.

Katie launches her Web site with a party, but a surprise appearance by James and a text message from Stassi threaten to ruin the event; Jax adjusts to life as an unemployed outlaw while Brittany adjusts to her new life as sole breadwinner.

When Stassi runs into her old SUR crew at Lala's party, Scheana must finally answer for her part in Stassi's sex tape scandal. Jax brags about his girlfriend's breast enhancement, but his friends are not impressed. Tom Sandoval works on a new single, Kristen continues her serial dating, and Tom Schwartz lands in hot water with Katie when he quits his job for Lisa Vanderpump.

Jax's girlfriend, Brittany, undergoes breast augmentation surgery. Lisa is faced with a big decision after James makes a scene at PUMP, Tom Sandoval removes the tattoo on his buttocks and Ariana makes a stunning statement at Katie's beach party.

Katie surprises Stassi in Palm Springs. Meanwhile, James continues to focus on Kristen; Scheana frets that she's losing her friends; and Jax, Tom Schwartz and Peter try to serve as babysitters.

Katie begs to hold her engagement party at Villa Rosa, but Lisa Vanderpump balks because Stassi and Kristen are on the guest list. Jax questions everything as his court date gets closer and Tom Sandoval shoots a video to launch his music career.

Lisa Vanderpump hosts Katie and Tom's engagement party; Stassi and Kristen stir up trouble; Jax must atone for his sins during a reunion with Stassi; Tom Sandoval performs his new song at SUR; Lala gets close to Kristen and James.

Kristen finds herself in the hot seat, Mike Shay makes his first reunion appearance to talk about his struggles with addiction and Lala discusses the difficulties of being new. Jax, Schwartz and Sandoval delve into their wild trip to Las Vegas.

The SUR staffers gather for a reunion installment. Here, James addresses notorious bite marks; Katie and Tom Schwartz talk about their proposal; Brittany reflects on how her life has changed; and Stassi tries to right some wrongs.

Stassi clashes with Lisa Vanderpump over her handling of the sex tape, Ariana campaigns against Kristen's comedy career, Katie explains the return of `Tequila Katie', and James and Jax get into an argument that nearly ends in blows.

Never-before-seen footage includes the most embarrassing, revealing and hilarious scenes from season four.