Leslie and Andy head to Washington to both visit Ben and April and hand in a proposal for Federal funding to clean up Pawnee's river. Leslie is disillusioned to find that she doesn't have a face to face meeting and that Ben is surrounded by attractive, capable women. Back in Pawnee it falls to Ron to host the employee appreciation barbecue. He makes it all about meat and no one has a good time. Tom and Ann are hiding the fact that they broke up from Donna to try and win a bet.
Ben has trouble getting respect from his interns and April. Leslie proposes a soda tax and then fears that if it passes she may lose her job. Chris and Tom help Andy get fit so that he can pass the Police exams.
Chris has begun therapy and comes up with a 311 line for the city so people can be directed to the right department. Ron is frustrated by the lack of response from public works and goes to fill in a pot hole himself. Andy comes along and thinks Ron is attractes to the lady who called in the problem. Leslie is trying to pass a bill to get the public swimming pool opened longer and has to do a deal with a sleazy councilman. April and Ben decide to take a road trip to Pawnee but get caught in traffic.
Leslie wants to give Pawnee seniors a sex education lesson because STDs are increasing. However Marcia Langman steps in to enforce the law that only Abstinence could be taught. Leslie breaks the law and receives a citation which makes her determine to break the law. Tom hits a fire hydrant while Tweeting and is sentenced to a week without any screens. Ron takes him out into the woods and is shocked to hear how dependent Tom is on technology. Ben and April are surprised by how robotic their candidate it.
At a Halloween film night organised by Chris, Leslie and Ann decide to scare Tom but instead give Jerry a heart attack. Leslie organises a fund raiser to help pay for his bills and is distressed to hear that Ben has been offered a new job in Florida. Ron helps Diane take her daughters trick-or-treating and it does not go well. He has to accept that the children will be a part of any future they might have together.
Ben and Leslie announce their engagement and everyone is excited. Ben is fretting about the engagement party because his parents hate one another. They do not get on and aren't mollified by Leslie's Knope-Wyatt Unity Quilt. Chris meanwhile gets very emotional at the party and needs a lot of help to calm down. Tom is busy preparing a presentation to secure Ron's investment for Rent-a-Swag but Jean Ralphio just wants to party.
Leslie is hugely proud of April for proposing a public project. However she says no when April argues that Lot 48 (behind Ann's house) is the most suitable location for a dog park. Ben is heading back to the accountancy firm but as he accompanies Tom on his search for investment he keeps receiving job offers. Andy's computer goes missing and he seizes the opportunity to practise his police work.
Leslie appeals to residents of Pawnee for new park designs. The best one to come in though is from a resident of Eagleton: Wreston St James. Leslie refuses to believe that he has good intentions despite how he charms Ben. The rest of the Parks Department are helping Tom fit out his store which he is concerned not to overspend on. Andy is stuck at work and is finding life as the weekend security guard pretty dull. April comes to play Burt Macklin with him.
Ron is up for an award for a chair he made and both Diane and Leslie go with him for support. When Tammy shows up Leslie has to be Ron's emotional guard. Meanwhile Tom, Donna, April and Andy are going out to celebrate Jerry's clumsiness. They are soon shocked to discover that he is having a Christmas party and they weren't invited. Inside Ben is protecting Chris from any emotionally awkward situations.
Leslie's bachelorette party goes awry when Leslie's conscience forces her to go retrieve Wamapoke artifacts which she planted at the park site to prevent a Paunch Burger from being built there. Ben's bachelor party is a quiet evening of board games until Tom suggests they go out. At a crazy new club the guys reveal that none of them has ever had a bachelor party. Chris decides that each should get to choose an activity that night and be the temporary bachelor.
Leslie determines to do something about the gender inequality in Pawnee's government. She and April go on a day's route with the sanitation department to prove that women can do what men can. Chris is supportive but distracted by his undefined relationship with Shauna. Meanwhile Ron is left in charge of Diane's daughters for two days. He survives the first but begs Ann's help on the second. Tom is struggling to connect with his basketball-loving clientele and asks Andy and Ben to help him out.
Ann announces to Leslie that she wants to have a baby and is looking into sperm donors. Leslie wants her to find a partner instead. After the sperm bank seems unappealing they trawl through Ann's ex-boyfriends and come across an unexpected candidate. Meanwhile Ben tries to find a caterer for the wedding and takes Ron, Chris and Tom with him. April has to lead a public forum on the new park.
Leslie has to raise fifty thousand dollars for the Park project or lose out to Paunch Burger. She sets up a huge marquee to hold a fundraiser but is then called in for the Annual Emergency Response simulation. Councilman Jam sabotages her and so she tanks the simulation to try and get back to helping Ben. Ben is struggling and puts Donna and Tom onto the tasks of chairs and food while Ron goes on Joan Calamezzo's show to invite people to the gala.
Leslie and Ben gather the gang and assign then tasks. Donna and Jerry take charge of the gala, Ron forges some rings while Ann makes the dress. Everyone is delighted with the impromptu wedding except for Councilman Jamm who is bitter and tries to ruin it. Andy discovers that he failed the Police interview.
The annual Correspondents' Lunch is a chance for Pawnee's government and media to roast one another. Leslie is all ready to attack the Pawnee Sun but is shocked to find that they have a copy of her speech and steal all her jokes. Ann is trying to work up the nerve to ask Chris to provide the sperm for her baby. Ben begins his new job at Sweetums charitable foundation and April tries to boost Andy's self esteem.
Leslie tries to keep the Pawnee VideoDome in business by awarding it historical status. Ron argues against any kind of bail out. April wants to apply for veterinary school and needs a letter of recommendation from Ann. Ann enforces a week-long friendship as her price. She is also anxiously waiting for Chris to tell her if he wants to be her sperm donor. Chris is unsure and Ben suggests he father Tom for a week who is dealing with an unruly new employee, Jean Ralphio's sister Mona Lisa.
Jam sues Ron for punching him and Tom, Andy and April try to help out. Ben takes Leslie to Partridge, Minnesota, the town where he became Mayor to receive a key to the city. Ann and Chris take a compatability test to see if they would make good parents.
Ron is ill and Ann takes him to the hospital. Chris fires the two employees of the Animal Control department. Leslie blocks Jamm's attempts to give the job away and interviews applicants. Ben takes Tom and Andy as he attempts to get a donation from Dennis Feinstein.
Pawnee throws a citizen named Ted into the lake because of how 'tea' is written in the town charter. When Leslie realises how many outdated laws are still in the charter she proposes to amend them. Garth Blundin objects and agrees to a contest with Leslie to live in a historic house with no modern technology. Meanwhile Chris tries to give Ron and April a management seminar while Ben and Ann fret over the perfect present for Leslie.
Jerry retires and Leslie, for once, is blindsided. She rushes to try and help him achieve some of the goals he entered government service with. However he's happy to reassure her that his family life is what he lives for. Tom frets that he will now become the new Jerry. Meanwhile Ann and Chris sleep together after freaking out about sperm donation.
Leslie and Ron take opposing positions on a subsidised mini-golf course. Councilman Jamm is the swing vote and enjoys being courted. Meanwhile Andy is outraged to see his band playing without him and Tom tries in vain to break up with Mona Lisa.
Andy finds a positive pregnancy test at Ron's cabin while the Parks Department are there celebrating Founders Week. It's all been a year of Leslie on the City Council and soon a coalition forms against her to get her recalled. Meanwhile April gets into Vetinary School and Tom receives an offer for Rent-a-Swag.