Marco is an anxious nineteen-year-old on the brink of adulthood, with three subjects to make up, a mother who lives with her smartphone in hand, and a brother who dreams of being an indie singer. He's anti-social and longs to experience love the way it used to be. Aria graduated the previous year, with "one day at a time" tattooed on her arm, and she lives each day as if it were her last. Following a wrongly memorized phone number, Marco and Aria meet and begin to develop feelings for each other... However, Marco is unaware that Aria lives one day at a time, not because she's as beautiful and rebellious as she tries to appear, but due to a degenerative disease that makes her go to sleep uncertain if there will be a tomorrow. A fun and gripping teen love drama that narrates the incredible and surprising journey that the protagonists will embark upon. All in pursuit of something as simple as it is complicated in today's world: falling in love.