When a heat wave hits Seattle, Station 19 becomes a cooling center. Andy deals with regret and finds a friend in Theo. Joey comes face-to-face with his past during a ride-along with Ben and Jack.

Without telling Emily or her parents anything, Bill decides with Zoe to test on Emily the biological weapon he hopes to be able to use against the aliens. Catherine, for her part, has had difficulty managing her grief since Mokrani's death. She now has only one thing on her mind: to find out who Bill Ward is and find him. Sophia is ready to help him, but Nathan hesitates.

Catherine, Sophia and Nathan make their way to London, accompanied by Victor, a survivor encountered by chance. Along the way, the dangers multiply. Sacha's feelings towards Emily intensify and the young man's behavior becomes more and more disturbing. Feeling threatened, Bill is forced to flee.

Korvo and Terry place nanobots in the city's water supply to spy on their neighbors. Learning they are not well-liked, Korvo and Terry use the information from the nanobots to win over the community, and run for president of their homeowner association. The nanobots form a sentient person that runs for president as well, and all three expose embarrassing secrets about their neighbors, who break out in violence. The incumbent president Ruth restores order and turns the crowd against Korvo, Terry, and the nanobot person, who escapes from Korvo. Jesse – concerned that Yumyulack is shrinking and capturing too many humans – uses technology to manipulate people who were mean to Yumyulack, hoping to teach him that humans are generally kind.

In a bid to save his marriage, M.O.D.O.K. takes Jodie back in time to a concert they missed when they were in college. During a detour to kill the child-version of his GRUMBL boss, M.O.D.O.K. and Jodie are attacked by college-aged M.O.D.O.K., who accidentally absorbs their time crystals, stranding them in 2002. The couple reconciles but is stuck in the past until they catch up to the present. Once in the present, they prevent themselves from ever going to the past in the first place, erasing their entire adventure from the timeline.

When the Pupa turns orange, Korvo realizes he left important Pupa information in his wallet on Shlorp. He and Terry travel back in time to the day they evacuated Shlorp, and knock Korvo's wallet into their spaceship. Returning to the present, they realize the Pupa merely ate something orange, but the time stream has been altered and they now live with Vanbo, an obnoxious Shlorpian. Returning to the past to set things right, Korvo and Terry learn they did not want each other as evacuation partners, but reconcile and beat up Vanbo. Yumyulack discovers Jesse has simulated a nicer version of himself in the "Pretend-O-Deck". His simulated self teaches him to be a better brother to Jesse, but one Yumyulack kills the other.

After the devastating alien attack, disparate pockets of survivors emerge into a shattered world. They quickly realise they must put their differences aside if they are to stand any chance of survival.

Due to a blood shortage, Grey Sloan Memorial sets up a voluntary donation center. Nick asks Meredith for help with his patient. Winston is hung up on his relationship with his brother.

The blood shortage continues. Meredith makes a risky decision regarding a patient. Owen's actions to help his fellow veterans come to light.

Lynette learns that no good deed goes unpunished when she momentarily befriends the mean Mrs. McClusky. Susan's mother decides to try and jump start her and her daughter's love lives. Andrew talks to a priest about his feelings, and tells him of his shocking plans for his mother, Bree. Gabrielle has her credit card declined in an upscale restaurant, and Carlos sends Gabrielle a big message about what will happen if she leaves him.

Gabrielle plans a big party to bid farewell to Carlos, who is about to head off to jail for eight months. Meanwhile George Williams resurfaces in Bree's life, much to Rex's displeasure. Also, Lynette is shocked to learn that Tom's old girlfriend Annabel Foster who he dumped for Lynette has been hired at his firm again. Meanwhile, Zach continues to stalk Julie while Mike tries to separate Susan from Mary Alice's past secrets. Lastly, housewife Gabrielle is suspecting that she's pregnant.

In a final and drastic attempt to save Nic from Lane’s acts of sabotage, Conrad must call in a favor from the one person he promised he never would.

Due to a blood shortage, Grey Sloan Memorial sets up a voluntary donation center. Nick asks Meredith for help with his patient. Winston is hung up on his relationship with his brother.

The blood shortage continues. Meredith makes a risky decision regarding a patient. Owen's actions to help his fellow veterans come to light.

Lynette learns that no good deed goes unpunished when she momentarily befriends the mean Mrs. McClusky. Susan's mother decides to try and jump start her and her daughter's love lives. Andrew talks to a priest about his feelings, and tells him of his shocking plans for his mother, Bree. Gabrielle has her credit card declined in an upscale restaurant, and Carlos sends Gabrielle a big message about what will happen if she leaves him.

Gabrielle plans a big party to bid farewell to Carlos, who is about to head off to jail for eight months. Meanwhile George Williams resurfaces in Bree's life, much to Rex's displeasure. Also, Lynette is shocked to learn that Tom's old girlfriend Annabel Foster who he dumped for Lynette has been hired at his firm again. Meanwhile, Zach continues to stalk Julie while Mike tries to separate Susan from Mary Alice's past secrets. Lastly, housewife Gabrielle is suspecting that she's pregnant.

A criminal lures Rosewood to the murder scene of a former tech millionaire and, in doing so, forces Rosie to re-examine a case from his past.

A blackout at Chastain Memorial Hospital requires the staff to treat their patients without the help of any technology. Bell orders the staff to stop accepting new patients and transfer those on life support, but when a child in need is rushed to the ER, Conrad and Devon go against the mandate. Meanwhile, Mina and Austin are tasked with performing heart surgery on a premature baby, despite the lack of power, and Nic works tirelessly to organize the staff and patients who stay during the blackout.

After firing some of Grey Sloan's best, Catherine continues to interfere with Meredith and Amelia's research; accidents at a climate change protest bring unique cases to the hospital; Bailey encounters a blast from the past.

Meredith and Catherine continue to disagree, and Meredith confides in Bailey for support; Richard, Winston and Lucas spend the day outside of the hospital; Blue deals with a relationship from his past; Levi meets the new hospital chaplain.

Bree begins to feel guilty about her friendship with George while Rex's health continues to depreciate. Lynette tries to spice things up with Tom who, she fears, is losing interest. Meanwhile, Mr. Shaw consults with Paul, and ends up lying to Susan. After talking with Kendra Susan learns what Mike did. Gabrielle tells John that she is pregnant, and John doesn't take the news well. Lastly, Felicia takes action to help Zach, and to get rid of Paul for good.

Susan and Mike decide to move in together, much to Edie's displeasure. Meanwhile, Lynette takes steps to make sure Annabel doesn't come between her and Tom. Also, Bree comes to a realization about her "buddy" George the pharmacist who continues to interfere in her and Rex's lives. Carlos' legal problems take a turn for the worse, when Gabrielle decides to leave him. Mrs. Huber's journal reveals some secrets. Lastly, two new faces arrive on Wisteria Lane.

When a heat wave hits Seattle, Station 19 becomes a cooling center. Andy deals with regret and finds a friend in Theo. Joey comes face-to-face with his past during a ride-along with Ben and Jack.

Megan unravels the details surrounding a stay-at-home dad's stabbing death in his suburban home. Megan enlists Peter's help when she takes on a Saturday carpool for Lacey and her girlfriends.

When a magazine editor is discovered dead in her Chestnut Hill mansion, Megan must once again slip back into the high society group she used to be a part of. In order to confront a prime suspect, Megan attends one of her mother's social events.

A criminal lures Rosewood to the murder scene of a former tech millionaire and, in doing so, forces Rosie to re-examine a case from his past.

When Melinda goes to visit friends who are experiencing problems with their house, she finds the ghost of six-year-old little girl who drowned. Melinda then tries to help the family of the little girl.

Megan unravels the details surrounding a stay-at-home dad's stabbing death in his suburban home. Megan enlists Peter's help when she takes on a Saturday carpool for Lacey and her girlfriends.

A criminal lures Rosewood to the murder scene of a former tech millionaire and, in doing so, forces Rosie to re-examine a case from his past.

When a heat wave hits Seattle, Station 19 becomes a cooling center. Andy deals with regret and finds a friend in Theo. Joey comes face-to-face with his past during a ride-along with Ben and Jack.

Bree begins to feel guilty about her friendship with George while Rex's health continues to depreciate. Lynette tries to spice things up with Tom who, she fears, is losing interest. Meanwhile, Mr. Shaw consults with Paul, and ends up lying to Susan. After talking with Kendra Susan learns what Mike did. Gabrielle tells John that she is pregnant, and John doesn't take the news well. Lastly, Felicia takes action to help Zach, and to get rid of Paul for good.

Relationships are challenged at Station 19 following Sullivan's actions at Maya and Carina's wedding, putting his marriage with Andy to the test. Dean comes to terms with his feelings for Vic, while Travis rekindles an old flame. The annual Phoenix Festival brings out some reckless behavior in some of Seattle's citizens, challenging the teams at Station 19 and Grey Sloan Memorial.

Andy and Sullivan's relationship continues to be tested. Meanwhile, Emmett joins Dean and Vic on a mental health call, and Maya does some soul searching.

When a heat wave hits Seattle, Station 19 becomes a cooling center. Andy deals with regret and finds a friend in Theo. Joey comes face-to-face with his past during a ride-along with Ben and Jack.

Bree begins to feel guilty about her friendship with George while Rex's health continues to depreciate. Lynette tries to spice things up with Tom who, she fears, is losing interest. Meanwhile, Mr. Shaw consults with Paul, and ends up lying to Susan. After talking with Kendra Susan learns what Mike did. Gabrielle tells John that she is pregnant, and John doesn't take the news well. Lastly, Felicia takes action to help Zach, and to get rid of Paul for good.