s01e 01 "Pilot"
- Walter's breakdown with Paige when he reveals that he knows what it's like to have blood on his hands from his actions versus his inaction.Walter: Don't lecture me about how people dying will make me feel because I already know....Walter: When I was sixteen, Cabe asked me to develop tracking software to drop military aid packages. Six months later, I turned on the TV and I saw bombs falling on Baghdad. They were using my software and I designed it for speed over accuracy. Two thousands civilians died.
s01e 02 "A Single Point of Failure"
- Walter's sister is dying of M.S. that's progressing at an increasing rate. Despite being a world-class genius, he can't do anything for her because he's not a medical genius.
- Cabe's backstory with his daughter.Richter: You think I care about getting caught, dying in prison? I died when my daughter did. I just didn't feel that I should be the only one to feel the pain I experienced.Cabe: You're not. I know what it feels like to sit at your child's bedside watching each breath they take, praying it won't be their last. To hold your daughter's hand and try to memorize what it feels like so you won't forget. Your daughter, too scared to close her eyes even when she's so tired 'cause she's worried she won't be able to open them again. Some things you just can't fix. You gotta live with them. You don't take innocent lives.Richter: That man deserved to die. They all deserved to feel my pain.Cabe: No, they didn't. No one deserves that.
s01e 12 "Dominoes"
- Sylvester was bought a weight-lifting equipment on his last Christmas with his parents, before he was dropped off to live with his uncle.
- Happy was sometimes returned from a foster home to government care a week before Christmas, just so that the foster family didn't have to buy her a gift.
- Toby was taken to the horse races every Christmas by his father. They made a lot of money, Toby got taught the secrets of professional gambling, and by the time they got home his mother would have already drunk herself into unconsciousness. The fact that he remembers all this fondly somehow makes it even sadder.
- Walter doesn't mention his childhood Christmas, but we know that he was living with his disapproving birth parents but still considers Cabe his true father, so it almost certainly wasn't good.
s01e 21 "Cliffhanger"
- Where to begin with this multi-megaton Drama Bomb? Walter finally learns Cabe's Dark Secret about how his programming was used to kill civilians in Iraq; feeling used and betrayed, he kicks Cabe off the team. Paige sees Ralph imitating Walter's suicidal heroism, freaks out, and decides to take him to Maine so they can live with Drew, even though he clearly doesn't want to go. All this leaves Walter emotionally shattered enough to drive around the LA hills at high speeds, which results in the near-fatal car accident that leads to the next episode.
- The guest stars also get into the act; the villain's motive for taking over the neurotoxicity lab is revenge for his fiancee, who was one of the civilians who died in Iraq. All this accomplishes is two more deaths; another scientist who worked at the lab (whose fiancee watches helplessly as he expires) and his own (as Walter watches helplessly, yelling "I don't want you to die!"). Sheesh!
s01e 22 "Postcards from the Edge"
- During his near-death ordeal, Walter keeps calling for Paige, who isn't there until near the end because she's busy getting herself and Ralph away from him, due to the events of "Cliffhanger". He also talks with his teammates about the good times they've shared; instead of cheering them up, this convinces them that Walter has passed the Despair Event Horizon.
s02e 09 "Arrivals and Departures"
- Megan, lying in a hospital bed, finally succumbs to her MS and passes away. The way her mom sobs as soon as she flatlines is just heartwrenching.
s02e 24 "Toby or Not Toby"
- Happy breaking down throughout the episode as the team race to save a kidnapped Toby from Mark Collins, who is threatening to torture him if his demands aren't met. Especially when Collins appears to go through with it. Walter quickly realises that Collins faked the screams they heard, but Happy looks heartbroken.
- When Happy learns that Toby was kidnapped while off buying her an engagement ring, she instantly decides that makes it her fault and won't hear otherwise. At the end of the episode, it becomes clear why: if she'd told Toby she was already married, he obviously wouldn't have been off on his own buying a ring and likely wouldn't have been kidnapped.
- ...And then the episode ends on one, as a rescued Toby proposes to Happy in spectacular fashion, with a song, a confetti cannon and a custom ring made from a nut, in front of the entire team... only to be told that Happy can't marry him, because she's married already. Cue alcohol.
s03e 03 "It Isn't the Fall That Kills You"
- Walter has been accidentally launched into space when a shuttle he was servicing got struck by lightning. Due to hypoxia, he starts hallucinating that Paige is with him, making her the only one who can get him to follow instructions to get more oxygen. This leads to her hearing his Love Confession, which she's forced to play to so he'll pull the lever thinking it's her hand. She cries as she promises they'll be together once he gets back, knowing she'll have to break his heart later. It should be a relief, but is still quite sad, when a recovered Walter is left with no memory of the incident besides a wistful craving for Baked Alaska.
- It also sets up a Tearjerker for later: Toby tells Paige that, if Walter has a subconscious memory of what happened to him, then one day it will be uncovered, and there will be fallout as Walter utterly fails to cope. The Baked Alaska craving indicates just such a subconscious memory, meaning that fallout is lurking ahead.
s03e 16 "Keep It In Check, Mate"
- Happy's dad's past comes back to haunt him when Cabe is forced to arrest him for wiping the VIN numbers of cars for a smuggler several years ago. Happy meticulously plans an escape, including leaving vehicles and keys ready for him to take and hacking the prison's electronic locks, because 'you need to walk me down the aisle'. At the end, Mr. Quinn doesn't take the escape option and surrenders himself, and Happy breaks down crying and raging at Cabe, asking him if he got what he wanted.
s03e 17 "Dirty Seeds, Done Dirt Cheap"
- Cabe, Happy, and Sly get exposed to neurotoxins that make them hallucinate their deepest fears. Sly's is chickens, Happy is rejection, Cabe is being too weak to protect people. Oh, and it's killing them.
- Walter isn't exposed to the toxin, but he has to confront his fears too. Specifically not being able to solve problems. Like watching a loved one die in front of him, for example.
s03e 22 "Strife on Mars"
- Walter finally regains his lost memories from "It Isn't the Fall That Kills You" and proves Toby's dire predictions of how he'll handle it to be sadly right on the money. He fires Paige rather than deal with the fallout, inventing "perfectly logical" reasons for doing so. She tells him to go to hell and walks out.Toby: You might be the only brain I'll never crack, 197. And I'm not sure I want to. Don't always like what goes on in there.
s04e 09 "It's Raining Men (of War)"
- Toby having to unpeel layers of supressed and altered memories in Cabe's psyche... until he finally recognizes the Awful Truth behind his father's death: he was shot in the act of trying to stop a robbery at a bodega when he drew a gun on the robber but was too slow to get a shot off before being shot in return, and Cabe was brought back home by the police wearing a wool blanket... that didn't comfort him but instead irritated his skin. Cabe had fabricated several memories until he couldn't distinguish the truth.
- Subsequently, Cabe blaming himself for what happened and breaking down in tears. Toby has to tell him upfront that it couldn't be his fault because adults are expected to do what he thinks he should have done when he was only nine.
Toby: Cabe, the only person responsible for your father's death is the man who shot him, not you.Cabe: (tearful) No, I froze...! I was responsible!Toby: You were a child...! Children don't stop men with guns.... Children make up stories, and you made up one. Perfectly popped popcorn and wonderful pine scents, and this impossibly picturesque loss of a father. Your story was so damn good, you believed it as an adult. You were just trying to protect this nine-year-old version of you, because, deep down, you blame yourself, because you were only nine years old. You were nine, Cabe. So now you're 59. Why don't you stop beating up on that little kid? Why is all this stuff coming up now? Why now? Because you think if you get sent to jail, you'll be failing us, like you think you failed your father. You think you need to protect us, like you thought you needed to protect your father. And that's why you haven't been coming around much the past few weeks-- guilt. Cabe, you did not fail your father, and you're not failing us. You've taken care of us for a long time. Now it's time to let us take care of you.
s04e 16 "Nerd, Wind and Fire"
- Happy and Toby are waiting for their results from the fertility doctor and Happy is stressed, convinced the results will show there's something wrong with her. While dealing with the Disaster of the Week, she finally gets Toby to hack the doctor's files... and Happy's results are normal. It's Toby who can't conceive. He looks devastated.
s04e 17 "Dumbster Fire"
- Walter, Sly, Happy and Toby get to see how the other half lives when they're rendered temporarily moronic by the Disaster of the Week. Afterwards, most of them manage to learn something positive from the experience: Sly learns the value of simple solutions, while Happy and Toby learn not to overthink things, all three putting these lessons to good use. Walter, however, completely rejects his lesson of accommodating other people and communicating, choosing to bury himself in work rather than go out with Paige.
s04e 22 "A Lie in the Sand"
- Walter's one little lie about going to a lecture Paige didn't want to go to with Florence instead snowballs into something that tears Scorpion apart. First he told her it was cancelled, then that he went to it without her (she assumed he meant alone, he didn't correct her). Finally she finds the two ticket stubs and confronts him.
- The lie turns out to be the last straw with Paige, who's clearly been unhappy with many aspects of their relationship and calls their "experiment" a failure. To twist the knife further, from the complaints she makes (his constant lecturing and unwillingness to accommodate others), if he'd managed to learn something from "Dumbster Fire," this might not be the end.
Paige: When I first met you, you were about nine, emotionally. Now you're maybe fifteen, sixteen. But I think that's as far as you can go. I don't hold it against you.- Florence walks in during the confrontation and tries to help, but ends up making it worse by admitting that she has fallen in love with Walter, leading to Paige accusing him of having an intellectual affair with her, cementing her conviction that she and Walter can't give each other what they need.
Florence: I don't know what I've walked into here...
Toby: A buzzsaw.- Florence's revelation enrages Sylvester, who accuses Walter - with examples - of "seducing" Florence, who clearly had no idea how he felt and looks horrified at having made things so much worse. Walter blows up at Sylvester, all but calling him a coward for not asking Florence out sooner. He and Sly actually come to blows, and Sylvester leaves Scorpion along with Paige.
- Finally, Walter rounds on Toby and Happy, who've been warning him about lying to Paige for two episodes, and effectively screams at them for having been right, asking if they're going to leave too. Without a word, they do exactly that, leaving Walter with only Cabe and Florence, and looking as if he'd like nothing more than to rewind the last five minutes.
- The episode - and series - ends two weeks later with Walter coming out of a pitch meeting and running into the newly-formed Centipede about to go in. The encounter is as awkward as you'd expect, each group acting cold and distant as if they hadn't been a family mere days ago.
