In 1928, a modern telecommunications company begins to operate in Madrid. The series tells the turn in life that four young women take when they start working for this company. The four of them feel attached in different ways, to their families, their partners, or their memories. Part of the focus of the show is the hardships working women faced in the 1920s.
Six months later, a catastrophic event deeply affects Lidia, Marga, Carlota, Ángeles and their loved ones. Marga gets a surprise visit from an in-law.
With her friends' help, Lidia puts her plan into action. Carlota decides what to do with her inheritance. Ángeles tries to earn Pedro Guzmán's trust.
Lidia's desperation worries Carlos and spurs Francisco to offer support. Marga helps Julio cover Pablo's job. Carlota finds a way to promote her cause.
Lidia and Francisco visit an orphanage to gather info. Complications arise with Marga when Julio impersonates housebound Pablo, who sneaks back to work.
Ángeles must deflect Guzmán's suspicion of a mole. Carlos learns his mother's car was sabotaged and confronts Lidia. Marga has a horrible realization.
To protect her child, Ángeles accepts a deal with Guzmán. A phone call gives Lidia a hunch on Eva's whereabouts. Carlota responds to her attackers.
Lidia turns the tables on her captor. During the king's visit, those fighting for Carlota's cause take drastic measures, forcing her to choose sides.