Merli Bergeron is a middle-aged philosophy professor who loses his apartment just as his ex-wife takes a job in Rome. He accepts the responsibility to raise their teenage son while moving them into his mother's apartment in Barcelona. A job opens at his son Bruno's school. Happy to be employed, he immediately disrupts the order among his colleagues and sparks discussion in his classroom, much to Bruno's chagrin. Each episode focuses on a particular philosopher and their ideas. Merli demonstrates Aristotle's Peripatetics (the act of movement to bring forth robust ideas...

Merlí encourages his students to write poetry, and visits the home of agoraphobic student Ivan. Tània coaxes Bruno into opening up to her.

Merlí gets a visit from Gerard's mother. Bruno thinks Eugeni is grading him unfairly because he's Merlí's son. Gerard falls in love at first sight.

During an overnight study session, Pol becomes suspicious of Bruno. Eugeni accuses Bruno and Pol of cheating on a test. Joan asks Merlí about justice.

Joan's father thinks Merlí is brainwashing his son. Bruno tries to console Tània after a friend betrays her. Merlí forces Ivan to go outdoors.

Berta acts out in class. Mònica invites Gerard to her home to work on a class assignment together. Gina learns Merlí has been seeing Laia.

Pol suffers financial and personal difficulties at home. Gerard finds evidence suggesting his mother has a lover. Joan rebels against his parents.

An intimate video of Mònica circulates among the students. At the museum, Marc spots Merlí and Gina kissing. Ivan learns his mother has a boyfriend.

The students throw a wild birthday party for Pol at Mònica's house, where Joan makes a drunken confession, and two friends act on a mutual attraction.

A major conflict erupts in Joan's family. Pol distances himself from Bruno. Gerard refuses to accept his mother's relationship with Merlí.

Eugeni gets a nasty surprise. Pol is tasked with tutoring Ivan. Merlí discovers Berta's hidden talent. A new student makes a strong first impression.

Joan refuses to participate in the school food drive organized by his parents. Oliver is ridiculed and shunned by his male peers, including Bruno.

Plans to discontinue Merlí's classes incite a protest. Joan acts on his feelings for Mònica. Bruno confides in Oliver. Ivan makes a breakthrough.

Joan asks Merlí for relationship advice, but Merlí gets a good tip from him instead. Tensions between Oliver and his mother reach a breaking point.

Merlí tells his mother a shameful lie. Things heat up fast between Gerard and Oksana. Finding himself attracted to his new boss, Pol confides in Bruno.

Millán tells Glòria a secret he's been hiding. Tània bravely speaks up to defend Berta in Coralina's class, but struggles to tell Marc how she feels.

When Pau is punished for throwing a pen at a mean teacher, Tània's help brings Marc closer to her. Pol and Miriam get into a heated confrontation.

When Coralina tries to get rid of a transgender substitute teacher, the students stage a protest. Marc seeks career advice from Bruno's grandmother.

Mònica gets fed up with Joan's jealousy. Gerard discovers what Oksana is busy doing every afternoon. Oliver reveals a painful memory to Merlí.

3 students decide to play a joke on Coralina, but it causes that they and two of the girls receive a punishment that at the end results in a very rewarding experience for all of them.

Coralina plants suspicion in Ivan's mind about his mother and urges Bruno to move to Rome. Joan tries to convince Mònica to change her mind.

Gina forces Gerard to face the realities of dating Oksana. Pol apologizes to Ivan. Marc brings Pau to visit their mom at work and makes a plea.

Joan decides to stop being the "nice guy" and try new things. Oliver makes an announcement to his parents. Bruno says goodbye to those closest to him.

Pol learns his brother is hiding a secret. The students sneak into the school at night and have a wild Christmas party. Karma catches up with Coralina.

On their way to school, Tània, Berta and Iván witness a disturbing incident. A class discussion about faith changes Oliver's opinion of Merlí.

Merlí makes a comment about Oksana as a mother that strikes a nerve. A class discussion about forgiveness spurs Pol to make amends for a past misdeed.

When Merlí gives an unfair test, Silvana urges the students to practice civil disobedience. Merlí tries to convince Gina that Gerard has deeper issues.

Tània overhears Pol making a rude remark about her and gets sweet revenge. Merlí takes Joan's father out for a night of fun. Ivan comes clean to Berta.

Merlí challenges Pol to dig deeper in a research project and consider why he resists his feelings for Tània. A good deed brings unlucky Iván a reward.

At the end of the school year, the students surprise Merlí with a tribute. Seven years later, a reunion reveals the paths each have chosen.