The eight new houseguests enter the house in three groups and choose their beds from three different rooms. For their first Food Competition, they are divided into 2 teams of four and must balance on two crossing beams while answering questions about each other.
The five exes are given passes allowing them to steal a bed from one of the original eight houseguests. Michelle, Amanda and Justin do not use their passes, but Robert and Jee use theirs to take Alison and Dana's beds.
In the Food Competition, the players win about half of their rations for the week but lose out on milk, meat, fruits and vegetables. The majority of the houseguests play a racy game of "Truth or Dare," which angers some of the older players. At the nomination ceremony, Nathan puts Amanda and Jee on the eviction block.
The houseguests learn that the Power of Veto is now the Golden Veto, meaning that eviction candidates can compete in the challenge and take themselves off the eviction block if they win the Golden Veto.
Dana decides to not use her Veto power, leaving Amanda and Jee on the eviction block. Amanda is evicted from the house by a vote of 9-0. In the next Head of Household competition, the players are asked to guess the majority opinion of the other houseguests when asked a series of questions. Jee lasts the longest and is the new Head of Household.
The remaining houseguests are divided into 2 teams for the Food Competition and given five mystery casseroles to eat and guess the two main ingredients. The losing team of Nathan, Michelle, Dana, David and Robert have to eat peanut butter and jelly for the next week while the winners receive full food rations. Jee nominates Erika and Michelle for eviction.
The Power of Veto competition involves throwing rubber ducks at a moving target in the pool, with points being awarded for closeness to the center of the target. Justin and David tie, and David wins the playoff round to earn the Power of Veto. Nathan and Jack try to convince David to save Erika so Jee will nominate Dana, but David decides to keep Erika and Michelle on the eviction block.
Michelle feels confident that she will not be evicted and is amazed (along with Jee, Robert and Justin) when she loses the vote 6-2. The remaining houseguests are grouped in teams of 3 and asked trivia questions; whomever answers first moves on to the next round. Dana survives the longest and wins Head of Household.
For the Food Competition, tiny parachutes corresponding to different types of food (including Burger King) are dropped from the sky. Everything the houseguests catch in their helmets will be their food rations for the week; they are very successful and earn a lot of food. Dana nominates Alison and Jack for eviction.
With Dana's eviction nominations, she has effectively moved over to the exe's alliance, a move that angers the original houseguests. In the Power of Veto competition, thousands of colored balls are dropped from a chute hanging over the houseguests' heads; the first player to fill his/her container with green balls wins the competition.
David is evicted from the house by a vote of 5-2. For the Head of Household competition, the remaining houseguests stand on a ledge holding a water cooler filled with ping-pong balls. They must try to dump as many balls as possible into a cylinder five feet below. Alison beats Jack by one ball and wins Head of Household.
For the Food Competition, the remaining houseguests are split into 2 teams and must connect pipes and joints through an obstacle course and route the water to a waiting rubber duck that will float across the finish line.
In the Power of Veto competition, each houseguest separately chooses four squares on a large grid where their picture is placed upside down. The houseguests take turns choosing squares from the grid; when all four of a player's squares are overturned, he/she is eliminated from the competition. With only Jee and Robert remaining, Jee sacrifices himself so Robert can win Power of Veto, which Robert chooses not to use.
Dana is evicted from the house by a unanimous vote of 6-0. For the Head of Household competition, the remaining houseguests are read statements and must guess which houseguest made the statement. Justin lasts the longest and wins Head of Household.
The remaining houseguests win full food rations for the week in a messy Food Competition. The "Three Stooges" alliance of Robert, Justin and Jee are courted by everyone in the household as Justin has Head of Household power. Justin nominates Jack and Nathan for eviction.
In the Luxury Competition, the houseguests win laundry service for the week rather than having to handwash their clothes. Robert wins the Power of Veto competition but decides not to use it, leaving Nathan and Jack as the eviction nominees.
Nathan is unanimously evicted from the house by a vote of 5-0 and will remain sequestered with Dana as one of the jurors who will help decide the winner.
After Robert and Jun leave the first cage, the remaining four players switch to the next cage. Jee makes a deal to leave his "Three Stooges" alliance and exits after Jack. Knowing Erika will last forever, Alison makes a deal with her to not be nominated in the next ceremony and exits the smallest cage, making Erika the new Head of Household. Erika nominates Justin and Robert for possible eviction.
Alison and Jun, who have hated each other so far, form a secret alliance as they are floating amongst the remaining alliances in the house. Jun wins Power of Veto and decides not to use it, leaving Robert and Justin on the eviction block.
Justin is evicted from the house by a vote of 3-1, adding further guilt to Jee for breaking up the "Three Stooges" alliance. The next Head of Household competition involves one round of bocce ball where each houseguest tries to roll a ball through a course and get closest to the hole. After everyone throws, Jee's ball is the closest, making him Head of Household for the second time.
In a new twist, the Power of Veto competition will be held before the nomination ceremony, but the Veto winner will not be revealed until after the ceremony.
Jee comes clean about the Power of Veto deal he made, angering everyone. He decides to nominate Jack and Erika for eviction to break up their alliance.
Jack is evicted by a vote of 2-1, leaving the female alliance intact. Before the Head of Household competition, certain items are removed from the house.
The houseguests notice Jun is gone and are very confused. They notice a giant apple in the backyard with a note informing them that this is the first of many clues pertaining to Jun's whereabouts; the first person to correctly guess will win Power of Veto.
The houseguests, jealous of Jun's excursion, plot to evict her from the house. Jun nominates Jee and Alison for eviction, knowing that Alison can save herself with her Power of Veto and wanting Jee out of the house because he's a strong threat.
Alison uses her Power of Veto to remove herself from the chopping block, and Jun replaces her with Robert. Jee is evicted by a vote of 2-0. In the Head of Household competition, the remaining houseguests are asked to complete statements made by evictees.
In the Food Competition, the houseguests must smash pinatas and collect as many fallen pesos as possible in 10 seconds. They gather enough pesos to earn food from four-star restaurants for the entire week. Robert nominates Alison and Jun for eviction.
The Diamond Power of Veto is up for grabs, meaning that whoever wins it can remove him/herself from the chopping block AND gets to choose who is evicted.
Jun, Robert and Erika do everything in their powers to convince Alison not to evict them. Alison elects to use her Power of Veto, removing herself and placing Erika alongside Jun as the nominees for eviction.
Alison wins Round 1 of the Head of Household competition after Jun and Robert quit due to the snowstorm outside. A mime is revealed to be a part of the next Luxury Competition and tortures the houseguests for the next few hours with his antics.
Robert tells Alison and Jun that if he is evicted, he will sway the jury to vote for the contestant who did not evict him. For the final round, Alison and Jun are asked a series of questions about their exes.
As Alison and Jun wait while the jurors debate who should win BIG BROTHER 4, highlights from the season are shown.
Alison and Jun are each asked a question by all of the jurors, and the jurors are very harsh and blunt in their questioning. After the jurors have finshed, Alison and Jun make one final speech in an attempt to convince the jurors.