Mariana becomes a drill sergeant as she tries to prepare for the Robotics competition. She, the girls (and Jesus) head to the competition and discover when they are there that their robot doesn't meat the weight requirement. Emma weighed the bot on a scale at home, and it's too heavy. The others want to remove the hanger on the bot, but Mariana refuses.
Jesus figures out a way to decrease the weight, but unfortunately when they enter it in to compete it stops functioning properly. The have to fix it before they can enter it again. They notice that their competition includes another all girls team that aren't very friendly, and a team made up of adults and professional engineers who probably shouldn't have qualified. Their former teammates also show up to watch them fail.
Lena shows up for support and to cheer them on but Mariana isn't too pleased about it and lets her know. Lena tells Mariana that she has to delegate better and that she can't rule with an iron fist and be so hard on her teammates, especially her brother.
The opposing team picks them apart and tries to knock them out of the competition. Mariana and her team come in 8th place, which is better than what the school previously came up as but Mariana isn't happy. Mariana convinces the other all female team to choose them as alliance members so that they can beat the team of adults. They work together to fix the hanger on their bot, and the girls (and Jesus) win the trophy.
Brandon goes home to practice piano. He spends the night at home. Later on Courtney takes offense to it thinking that he's still upset with her about her speaking with his father. He tells her that he's just trying to focus on his audition and that he doesn't have time to convince her that nothing is wrong with their relationship at the moment.
Brandon and Stef have a heart to heart where Stef apologizes for making him think that she only held him responsible for what happen with Callie. She tells him that she hopes he isn't letting his relationship with Courtney hold him back from his dreams and doing his best with his Juilliard audition. They make up.
The police come to tell Callie to back off and stop harassing the child molester. Stef lectures her about getting involved and she tells Callie that she's working on the case. Callie doesn't heed her advice because she and Aaron spend the day trying to get as much information as possible about what happen with the murdered victim.
They find out that there was a curbpainter and that the person who did that may be the killer. They track him down to his apartment. When they knock there is no answer so they stake out his home waiting for him to come back. When he does, Callie finally decides that she should let the police do the work. She and Aaron leave.
Stef investigates the molestation case of the child molester in the Kyle case. She talks to his victim and discovers that one of the detectives was responsible for getting the kid to retract his statement. The detective is essentially the reason that the child molester was able to make a deal and go free and that Kyle is still in jail.
A realtor comes to see the Fosters home. She tells the moms that they have to clear it out and remove the pictures so people can imagine themselves being in it. She suggests that they show the house when the kids aren't there. While showing the house to potential buyers, she walks in on Callie and AJ undressed.
At the end of the episode it is revealed that the couple who saw the house liked what they saw. They put in a bid for the house and paid more than asking price. The catch is that the family has to be out of the house by the end of the month.