Season 1: We meet a glamorous-looking Agnes (Antje Traue)in 1953 as she's arriving in Winden with her young son Tronte. The first person she meets is a lost and beat-up Ulrich who just time travelled from 2019 and is wandering the highway in Winden trying to figure out what just happened. Her next stop is to the house of Egon and Doris Tiedemann, where her and her son are renting a room. We don't know much about Agnes and her past, but what we do know is this: there is definitely some sexual tension between her and Doris from the minute Agnes enters the house.
Season 2: In 1954, Agnes is still living with the Tiedemanns except now her and Doris are having an affair. We get a few answers about who Agnes really is after she meets with the older Claudia, when it's revealed that not only was she was once part of Sic Mundus (Adam's group known also known as the travellers), but she's also Noah's brother (and it sounds like she had a falling out with both parties). In 1921, we get a glimpse of Agnes as a little girl, sweeping the floor of her mother's inn where a teenage Jonas is recovering from the wounds he inflicted in 2053. In the season finale we meet Agnes again at the Sic Mundus headquarters (her hair styled in the same crown braid she wore as a child) where she surprises everyone and kills her brother as he's trying to kill Adam.
Season 3:
- Adam's World: Agnes has been missing from the '50s for months, and when we first see her, she's in the future with Adam, who gives her the newspaper clipping that will later inform old Claudia of her own death. We see her enter the chamber in the power plant with the dark matter in a yellow hazmat suit, then don't see her again until we're shown the flashback of her killing her brother, Noah.
- Eva's World: It's unclear exactly how Agnes goes on to exist in this world, as Silja's birth seems impossible, but for Ulrich to exist, she has to! However, we don't see her in this world throughout the season.
- Origin World: Agnes can't exist without time travel, as she's the daughter of Silja, who also only exists due to time travel.