Nick, Noah and Grace are walking home from school. When Noah takes off, it gives Nick and Grace a chance to talk, and Grace learns that Nick has been thinking about breaking up with Courtney. Grace is surprised that Nick hasn’t actually brought his feelings up with Courtney and she encourages him to be honest with his girlfriend.
At Grey House, Sam pays Cassie a visit and is surprised with how distant she is. He calls her out on her odd behavior and Cassie comes clean and says Joanne told Cassie about Sam never wanting to get married again. Sam says he knows he isn’t good at marriage and he wouldn’t want to hurt Cassie. Cassie admits that now that she knows Sam’s stance on marriage, it makes their relationship feel different.
The next day, Michael and Vanessa stop by Cassie’s shop to talk about their wedding plans. A small jewelry box catches Vanessa’s eye. When she opens it, she finds a pile of coins from Cassie’s travels. Cassie explains that it is a Middleton wedding tradition to take a coin and toss it off the footbridge the day before getting married for good luck.
Courtney meets Nick at the coffee shop and she is already dismayed by Nick’s distant behavior. Nick tells Courtney there is something he wants to tell her, but before he can break up with her, she invites him to a friend’s party and he accepts the invitation.
Joanne stops by the shop to pick up some tea, and she and Cassie catch up. Cassie assures Joanne that she and Sam will be just fine. In fact, she has a friend in Chicago she visits twice a year who always has great advice, and Cassie is long overdue for a visit.
Cassie gets to Chicago and as soon as she checks in to her hotel, she pays her friend Olympia a visit at her book store. Olympia senses that there is trouble in paradise when it comes to Sam and Cassie, and agrees to go get tea and catch-up. Cassie admits that she and Sam were fine until she found out he never wants to get married, again. Olympia’s advice to Cassie is to live in the moment and stop being so focused in the moments that follow. She believes that when you live in the present, you still get to be surprised by what life throws at you.
Joanne and Sam grab a meal at the microbrewery, where she wants to talk further about Sam’s stance on marriage. Sam says it is easy for Joanne to talk because she has never been married before. As soon as he says the words, he feels guilty. She says the reason why she never got married is because she never found someone to love as much as Sam loves Cassie, and begs him to not let her get away.
Noah and Grace are walking home when they are interrupted by Courtney. Grace is shocked to learn that Nick agreed to go out with Courtney this weekend, especially when Grace thought Nick was planning to break up with her. The two girls spot Sam taking off in his car. When Grace wants to know where he’s headed, he tells her he’s taking a one-day trip to find Cassie.
Sam arrives at Cassie’s hotel searching for her. He ends up booking a room, in hopes of surprising Cassie when he sees her.
The next morning, Sam heads to the lobby and finds Cassie, who welcomes him with a hug. He tells her he knows that things are complicated, but she stops him and says she is ready to just live in the moment when it comes to their relationship.
While at the Bistro, Martha purchases a muffin and finds a Chinese coin underneath the tray. She says that maybe it will bring her good luck. Just then a delivery arrives to the Bistro of containers filled with live lobsters that Elizabeth ordered for the wedding.
Sam and Cassie pay Olympia a visit at her book store. Sam takes a second to look around at the bookstore in search of one about Episodic Ataxia.
Back in Middleton, Elizabeth introduces Mike and Vanessa to the horse and carriage they will be riding in for their wedding. Vanessa speaks up that this wasn’t what she and Michael wanted; they just wanted a simple ceremony. In fact, now she doesn’t want to get married in Middleton at all!
The next morning, Cassie comes home to find Elizabeth getting ready to leave Grey House. She tells Cassie that the wedding is off and wants advice from Cassie on how to spend her remainder of time. Cassie recommends taking a journey across the footbridge near Eternity Creek.
Vanessa and Michael are taking their own trip across footbridge and toss in the coin that Cassie gave them earlier. Martha surprises them on the bridge and tosses her own coin in honor of her son and future daughter-in-law. Elizabeth shows up on the bridge, too and says she is taking the time to discover Middleton’s scenery. Vanessa and Michael have a big announcement for their moms: they want to get married at City Hall tomorrow! Martha agrees to keep the decorations to a minimum and she also agrees to officiate!
The wedding day has arrived and Vanessa and Michael’s friends have gathered around in City Hall. The bride and groom start their vows by giving thanks to everybody who has helped bring the last-minute wedding together.
To begin, Martha recites meaningful words that Cassie found for her to read. "They're about to say 'I do.' Three little letters, two little words. It's the simplest part of the day. But there's nothing simple about the things that will remain unsaid. 'I do' means I do know I could be hurt. But I'm ready to be healed with you. It means I do want to try. Even when the fear of failure holds me back. And I do not know the future, but I'm ready to be surprised along the way. And 'I do' means I do want your love and I do give you mine. And nothing we do will ever be the same. Because you and I will be doing it all together."
Later on at the reception, Elizabeth credits Martha with how beautiful the wedding ceremony was. Martha says she couldn’t have done it without Elizabeth’s help.
Grace corners Nick at the wedding and asks he if has broken up with Courtney yet. Courtney overhears the question and tearfully runs away as Nick chases after her.
Joanne is saying her goodbyes to Sam before taking off for the airport. He presents her with a gift he found in Olympia’s bookstore. She is pleasantly surprised that it is not a medical book, but instead one of her favorite books from high school, “Walden,” by Henry David Thoreau. She points out that she loves it so much because it is about letting life just happen. The two share in a tearful goodbye and she leaves.
Martha finds out that no one officially canceled the horse and carriage, and they are waiting outside. Instead of letting a good horse ride go to waste, Sam says he and Cassie will take a ride in the carriage. They end up at Hudson’s Mill and start talking about the future. Sam starts talking beyond the future, and wants to start talking about forever. He gets on one knee and proposes to Cassie. She responds with an astounded yes and the two share a passionate kiss.
They head back to Grey House, where Nick and Grace are arguing loudly. Before Cassie and Sam can share their good news, Grace and Nick storm out in opposite directions. Sam says that despite their kids fighting, he still has absolutely no second thoughts. That said, it is time to buy a ring for Cassie. She smiles and says she has been keeping her left ring finger free for Sam.