Former high school classmates Kevin Berrigan and Cassie DeMaio meet again by chance forty years later when they attend the wake of her uncle on Long Island.

On the day of the funeral, Kevin rushes to Cassie as she was about to leave the cemetery with her friend Claire and Cassie's eldest daughter. Cassie was impressed by Kevin's gallant effort to catch her that she slips him her email address.

Initially Kevin and Cassie exchange emails, which then develops into pop-up messaging. After Cassie coaxes Kevin into getting a webcam for his antiquated PC, they each then graduate up to exchanging video chats.

Cassie arrives back to Long Island for Mother's Day weekend. They make arrangements to stay for a few days with Cassie's mother. But that Saturday evening Cassie is picked up by Kevin for a dinner engagement with Claire and her husband and Kevin's best friend Peter and his wife

While the dinner went well between the three couples, Kevin's plans to have Cassie come over for an hour or two at his home do not. She reasons with him that it wouldn't look good in the eyes of her mother and daughter if she didn't return home by a reasonable hour. Cassie promises Kevin there will be another time for that, although he remains skeptical. He nonetheless concedes to her wishes.

Three days later, Kevin sadly prepares to leave Cassie, but not without extending an invitation to her to stay at his home. She agrees to come down in mid-September for a few days before she decorates her store with a Halloween theme. It is on her first night with him on a romantic dinner out when Kevin proposes to Cassie. After discussing a few issues, she accepts.

After discussing the marriage plans with relatives, Kevin and Cassie ask Claire to be the matron of honor and Peter to be the best man, both of whom accept.

On her last night at his home, Cassie experiences sharp pains in her head, alarming Kevin. Very concerned over her well-being, Kevin repeatedly asks Cassie if she is capable of driving five hours given her issue. She insists she is fine.

Cassie then has an episode with her business partner on her return to the store in Carthage, where she blanks out in the middle of a question posed to her. Cassie is then strongly encouraged to go home and get some rest.

In the meantime, Kevin does some research and comes across the name of a renowned neurologist and have an MRI and CT scan. She eventually agrees.

Days after the exam, Kevin gets a call from Cassie's mother, asking him how he's coping with the news. Kevin is dumbfounded by her statement until she confesses that Cassie is diagnosed to being in the early stages of Alzheimer's. Shocked by the revelation on different fronts, Kevin tells his staff and another dentist that he has to leave for his home immediately. That is when Kevin questions marrying her.

Kevin arrives home with spews venom at Cassie forcing him to leave. After consulting with Peter and his wife, he reconciles to do the right thing and return to his home and make up with Cassie and continue with the marriage plans. He also assures Cassie that he is all in with her in battling the illness.

Five months later. The big day. And after Kevin accepts her to be his wife at the altar, Cassie gives him a long gaze. Convinced that this is the man for her, Cassie says "I do" when prompted to take Kevin on as her new husband.