David Levithan's Another Day follows a high school student named Rhiannon. Rhiannon is in a relationship with her boyfriend, Justin. Often, Justin is distant and uncaring towards her, causing her to consider breaking up with him. However, things change overnight. One day, Justin seems entirely different. He is more kind, attentive, and genuinely interested in getting to know her. She doesn't feel like a burden to him. That day, they skip school together and have a wonderful time together. Meanwhile, Rhiannon feels a connection like never before. Little does Rhiannon know that Justin isn't really Justin on that day. His body has been inhabited by A, who wakes up in a different body each day.
Soon after, A reveals their true identity to Rhiannon. They explain to Rhiannon the complexities of their condition and life in general. Initially, Rhiannon struggles to believe and even understand A's situation. But as they spend more time together, she starts to accept A's condition and starts to fall in love with their mind—not just their body.
Rhiannon is conflicted between her feelings for Justin and her feelings for A. Although her relationship with Justin isn't especially strong, he provides her with something she craves: a sense of stability and normalcy. Although she feels a genuine connection with A, their relationship is fraught with challenges because of A's condition. To that end, Rhiannon considers what love truly means to her. Specifically, can she truly love someone whose physical appearance changes daily? And can she have a future with them when she doesn't know where they will end up each day?
This causes Rhiannon to consider the future of her relationship with A. She finally realizes that, although she has deep feelings for A, a relationship with them will be impracticable and cause her tremendous emotional strain. As such, she decides she cannot have a romantic relationship with them.
