"A Spark. To Pierce the Dark." is the 105th episode of Desperate Housewives.
Susan is surprised to see Karl at the school and he tells her his son Evan is now enrolled. Susan tells Karl that she does not want any of her co-workers to know that she now has two ex-husbands walking the halls. At school, Susan asked the kids to draw something that made them happy. She is shocked when Evan shows her a drawing of a man stabbing another man in the gut with a sword, which makes him happy. Karl tells Susan that she still hates him and doesn't want his son in her class, Susan denies it but Karl believes she is stuck in the past and is just blaming him for what happened between them. Susan throws paint in Karl's face when he shouts that her behavior is why no man will stay with her. The next day, Evan draws a picture of him stabbing a woman with a knife. When Susan shows Karl the drawing, he tells her it's Marisa. Susan asks why Evan would draw that and Karl tells her it's because she left them as she couldn't handle being a mother.
Lynette & Gabrielle
Meanwhile, Lucy tells everyone that until the deal closes everyone is working through lunch and on Friday nights which conflicts with Lynette's schedule as she coaches Penny's basketball team. Lucy scolds Lynette for touching her expensive figurine collection. Lynette asks Carlos if he could talk to Lucy and try to get her to tone it down as he is the President. Later, Lucy figures out it was Lynette who complained to Carlos and informs her that Friday nights are now permanent work days.
Gaby tries to get Carlos to have sex with her but he tells her that he has to go back to work or he is too tired. Later, Gaby is bored because all her friends are working so she has coffee with Tom. Gabby complains that Carlos doesn't want to have sex with her but Tom tells her guys always want to so she needs to get past the tired adult and find the horny teenager in Carlos. Gaby takes the kids to work and has Lynette watch them while she talks to Carlos. She reminds him that they are on the path of becoming their old selves. When Juanita and Celia want to play with Lucy's figurine collection, Lynette allows them to and when Lucie sees them she mistakes them for the cleaning lady's and yells at her. Carlos decides he wants a different future for the company and fire Lucy, which pleases both Gabby and Lynette.
Bree is upset that she is paying the therapist $200 an hour and has not made much progress. Orson tells her that he is stealing to hurt Bree. He tells her that for the past year she has slowly brought him closer to being a eunuch. Orson is mad that Bree keeps putting her company before him. He warns her that soon, Orson Hodge will disappear. Bree decides that the best way to save her marriage would be to sell her company. Before she signs the papers, Andrew tells her that if Orson really loved her then he wouldn't make her give up the thing that makes her happy. Much to Orson's disapproval, Bree refuses to sell her company and plans on doing a second cookbook. Orson warns her that he might steal again but she tells him to steal whatever he wants but he will not be stealing her company.
Dave phoning the rangers station informing them about illegal hunters in the area. Mary Alice explains Dave's steps in carrying out the murder. First, Dave will guide Mike and Katherine to a remote cabin. The next morning he will pretend to be sleeping while Mike and Katherine go on a hike. Dave will grab his gun and follow the two and once they stop to catch their breath, Dave will pull the trigger, breaking Mike's heart. The rangers will tell Mike about the report of illegal hunters. Dave will drive Mike home, enjoying his pain.
Back at the Gazette, the intern faxes Edie the article explaining Mike's involvement in the crash that killed Dave's family. Unfortunately, Edie is out of paper so she calls Karen to see if she has any fax paper but when she doesn't, Edie tells her she will go to the store tomorrow and asks Karen if she needs anything, when her list becomes too long she tells Karen she will just call her from the store. The next day, Edie tells Karen that Dave lost his wife and 3-year-old daughter which makes Karen sorry she ever doubted him. Karen invites her over for drinks, which postpones the fax from coming through again. Edie finally puts the paper in and receives the article about Mike.
Back at the cabin, Mike is sleeping and Dave tells Katherine that his knee is really bothering him and is going to skip the hike but convinces Katherine to go with Mike because it would be romantic. Katherine tells Dave that he always has a good attitude and takes everything in stride. Dave tells her he has had to make himself happy and when she asks if he is happy, he replies "I'm getting there." The next morning Mike and Katherine head out on their hike while Dave pretends to sleep. He grabs his gun and follows them but just as he is about to shoot Katherine, Edie texts him saying she knows everything and to come home immediately; therefore, Dave misses and hits the tree Katherine is standing by. Katherine wants to leave so they head home.
Dave comes home and Edie tells him she knows the only reason he wanted to move to Wisteria Lane was to get close to Mike. Edie believes the only reason Dave married her was so he had a cover story. Dave tells Edie that Mike took everything he loved and was never punished so he needs to make things right. Edie tells Dave she is calling Mike to warn him before Dave does something stupid. Dave grabs the phone and begins to strangle Edie but just as he is about to kill her, he lets go and she runs out of the house and starts driving away. Meanwhile, Orson breaks into an old lady's home but she catches him and hits him in the head with baseball bat. Orson runs out of her house and walks down the street where Edie who is trying to call Mike, is about to run into Orson but she swerves and crashes into a pole. Edie gets out of the car but fails to notice the water she is standing in and when the car door touches the power line she is electrocuted as her hand was grasping the car door. The episode ends with a close up of Edie's hand twitch.
- The title comes from the song "Broadway Baby" from the Stephen Sondheim musical Follies.
- The episode title is the first and only title to use a full stop.