Early morning of January 1, 2016. Oscar goes to a nightclub with his ex-girlfriend, Vero, believing he still has a chance with her; but he is wrong. It is the same discotheque where Ana works as a waitress. When the disco closes, Ana and Oscar meet at a bar.

December 31, 2016. Ana has signed up for the dinner that Guille and Ali have organized at her parents' house in the mountains. Óscar has a tense relationship with Vero. Ana has been dating Javi for about five months. While they wait for Oscar's father to arrive, they entertain themselves with a game during which all the tensions of the night will explode.

Morning of January 1, 2018. Oscar and Ana have been together for ten months. They both have a horrible hangover. They have celebrated New Year's Eve in her apartment and it's a mess; but they don't care. They only have one plan: to spend the day in bed. They are happy and in love.

December 31, 2018. Óscar and Ana have been living together for six months and are very happy; but Ana has just been offered a job in Edinburgh and is looking forward to living there with Óscar for a while. They have invited Isabel and Fernando, Ana's parents, and Carmen, Oscar's mother, to dinner.

January 1, 2020. For some months now, the distance has been between Ana and Oscar, and so they have decided to make a quick trip to Berlin where they will stay for only twenty-four hours: a whole day to get to know the city, enter one of the most famous clubs and meet again.

Early morning on January 1, 2021 at the emergency room of La Paz hospital. This is the first Christmas COVID. Although Oscar finished his shift hours ago, he is still working. Partly to lend a hand and partly because he doesn't want to go home. Oscar leaves the hospital and goes to an illegal party with Guille, Palo and Ros.

31 December 2021. Anna lives in Lyon and has a boyfriend, Manu. She has set up a catering with her friend Silvia, "Spanish Delicias." Her sisters Rocío and Irene have gone to visit her with her mother, Isabel, to celebrate New Year's Eve with the family. Ana just found out something important.