YOU'RE NOT YOU
NOTE: This spoiler was submitted by Jeremy

It is the day of Kate's (Hilary Swank) 35th birthday. She and her husband Evan (Josh Duhamel) are having sex in the shower. At night, they host a dinner party for their closest friends. Kate is a skilled pianist, and so she plays a tune for everyone to hear. Suddenly, her hands begin to shake...

A year and a half later, we meet Bec (Emmy Rossum), lying in bed with the man she slept with. She wakes up and realizes she is running late to a job interview.

Kate has been diagnosed with ALS and has lost most of her motor skills. Evan has been trying to help her as much as he can while a caregiver has been around for Kate. She let the last one go for making her feel like a patient, and she is hiring a new one. Bec arrives at their home for the interview. Although she doesn't make a good impression with Evan, Kate decides to hire her after Bec says she took care of her grandmother when she had ALS.

Bec's first time with Kate involves helping her onto the toilet and then wiping her. Bec is clumsy at it and accidentally falls down with Kate after trying to wipe her.

Bec has drinks at the bar with her best friend/roommate Jill (Stephanie Beatriz). She was also up to perform onstage, but she is too nervous and runs away to throw up. She meets Wil (Jason Ritter), who is attracted to her and tries to make her feel better about singing. Bec also runs into one of her college professors, Liam (Julian McMahon), with whom she had an affair. Liam is with his wife, so, out of spite, Bec hooks up with Wil and sleeps with him. The next morning, he cooks her breakfast, but she rejects it due to her not being "girlfriend material."

Bec constantly shows up late to Kate's house, so the latter tells her not to give anymore excuses. Bec does try as hard as she can to help Kate. After putting her to bed, Kate asks Bec to hand her the laptop to check Evan's emails. Reluctantly, Bec shows Kate, and she learns that he is having an affair with his secretary Cynthia (Erin Chenoweth).

While home alone, Kate tries to walk by herself. She ends up falling down the stairs and sends Bec a blank text, alerting her. Bec makes it to Kate's house and helps her up. She helps her take a shower, and Kate tells her she doesn't want to be there when Evan gets home. Bec takes her to her own apartment.

Kate asks Bec to drive her to a clinic, as she blames herself for Evan cheating. Bec refuses to let her stay there and instead takes Kate to confront Evan at his office. She tells him she is moving out, and then calls out Cynthia as Bec wheels her out of there.

Kate experiences coughing fits and has difficulty breathing. Her speech has also started to become impaired. She does not want to take any experimental drugs to help her. Meanwhile, Bec continues her affair with Liam.

Bec takes Kate to the public pool where they meet another woman with ALS, Marilyn (Loretta Divine), and her husband John (Ernie Hudson). They get together, along with Jill, and they get high. There, Kate starts cursing, even after telling Bec not to do that.

Bec brings Kate with her and Jill to the bar where she tried to perform. There, they meet up with Wil, who charms Kate. Kate thinks he is a cute and nice guy and that Bec should give him a chance. On the drive home, Kate mentions another man that she loved before marrying Will, saying that nobody ever looked at her the way he did.

Bec takes Kate to a party at one of Kate's friend Alyssa's (Andrea Savage) home. Kate asks to hold Alyssa's baby, but she starts coughing and nearly drops the kid.

Evan comes back and tries apologizing to Kate for what he did. She has Bec speak for her, telling Evan that she's not upset about the affair, but that she was feeling invisible after being struck with the disease.

Kate and Bec become closer as friends, going as far as having a Thanksgiving dinner with Marilyn, John, Jill, and Wil. Wil and Bec dance together. Moments later, Liam shows up at the door, trying to kiss Bec, which Kate sees.

Marilyn is in the hospital and is put under a ventilator. Kate asks Bec to not let her end up like that.

Bec is invited to lunch by Alyssa and Kate's other friend Keely (Ali Larter). They ask if Bec has been put in Kate's will, which Alyssa seems ticked off at since she doesn't consider Bec to be one of Kate's friends unlike herself and Keely.

Evan returns again to see how Kate is doing. She tells him that she knows he didn't see her for who she was, but she wanted to be the woman he saw, so it's both their fault that the relationship didn't really work out.

During Christmas, Bec gets an unexpected visit from her parents (Gareth Williams and Marcia Gay Harden). When Bec and her mother go into another room, Kate and Jill overhear them arguing, in which they learn that Bec dropped out of college. Bec is angry because she feels that her mother keeps expecting her to screw up. After they leave, Kate asks Bec to leave, thinking she has caused Bec to put things on hold. Bec is hurt by this.

A while later, Bec comes by Kate's home to tell her and Evan that Marilyn died. They attend her funeral, where John recites something that Marilyn wrote, calling herself the "black Lou Gehrig".

Kate's parents (Geoff Pierson and Frances Fisher) come to take care of her. Kate has another coughing fit and she can't breathe. She is rushed to the hospital, where her parents learn that she gave Bec permission to decide what happens to her instead of Evan. Bec runs over to find this news as well. Kate's mother begs Bec not to take Kate away from her. Bec says she only wants to take her home, knowing that Kate did not want to end up using a ventilator.

Kate is brought home. Bec and Evan keep her company, even helping her play the piano again. However, the thought of seeing Kate this way is overwhelming for Evan. He has one final moment with his wife and hugs her before leaving. With Bec by her side, Kate asks her to promise to find somebody that sees her for who she is. Bec thanks her for not expecting her to fuck up like everyone else.

At night, Kate starts to have trouble breathing again, which Bec can hear in the next room. She knows she cannot help her, but she runs to Kate's side and holds her until she is gone.

The last scene has Bec sitting outside her place on the steps. Wil walks up to sit next to her. It is implied that she is keeping her promise to Kate.

The credits show Bec singing at the bar.