An illegal rave in Munich's catacombs goes wrong and reveals a network of social outcasts living underground.
When fire breaks out at the underground party, chaos takes hold; with her best friend, Janosch, Nellie sets off to search for her brother, Max; the corpse of the first missing person appears.
Nellie seeks help from an unexpected source in her search for Max, uncertain about who she is dealing with; Anna Mahler gives an interview on TV; Lisa Limberger sees her social project imperiled by the party and by an ambitious CEO.
Nellie discovers the truth about Janosch's origins, while Tyler and her family are divided about how to handle their guests; an argument splits up Nellie and Janosch; Lisa falls in love and finds new allies.
Nellie is on the brink of finding Max when another body is discovered; Lisa, under pressure as the city is withdrawing its support, places all her hopes on the Inspire Project; Liebknecht finds who Kaltbrunner is looking for.
Tyler and Nellie join forces, while Janosch makes a discovery about a relative; Frank Limberger wants to replace Lisa at the company; Liebknecht informs Kaltbrunner that she is on the brink of solving the case.
Nellie and Tyler put their lives at risk to save someone; a new clue leads to the terminally ill Liljana; Nellie and Janosch attempt to reconcile; Lisa takes on a new role at the company.