In early 2020, neurologist Dr. Tony Wong, Tony Leung Chiu Wai, travels from Hong Kong to Marburg to continue his research on newborns' brain activity at Marburg University. But shortly after his first class, the COVID-19 pandemic disrupts his plans. Forced into lockdown, he adapts to a new life and grows fond of the nearby Botanischer Garten Marburg, where he becomes attached to an ancient gingko tree dating back to 1832. Guided by video calls with Dr. Alice Sauvage, Léa Seydoux, he develops a novel approach that attempts to correlate his neural signals with the tree's activity. With a makeshift brain scanner mounted on the tree, he senses a possible link between what is seen and what remains unseen. Trouble arrives when Anton, the campus janitor, Sylvester Groth, grows distressed by the project and destroys the equipment. Alice responds by sending the male form of the gingko's gymnosperm to fertilize the campus's solitary female. After the equipment is damaged, Anton begrudgingly comes to terms with Wong, offering him a local German dish. Together, they watch the fertilization process unfold through the scanner, pondering the delicate balance between science and nature.
In 1908, Grete, Luna Wedler, a young German feminist, seeks to become the university's first female student. During her interview, the botanic department's board attempts to humiliate her with sexist questions about Christian Konrad Sprengel's plant reproduction theory. Distressed but prepared, Grete answers calmly and, drawn to the garden's quiet spaces, she seems to connect with the old gingko tree. She is found by Thomas, who reveals that she was the only woman accepted by the committee. After attending a female group gathering at the gingko tree, in the early morning hours, Grete is expelled from a family home where she rented a room, accused of promiscuity. Sheltered by Herr Fuchs, who hires her as his assistant photographer to his studio, Grete discovers a passion for professional photography, capturing her research subjects with growing confidence. At the University, she applies to join Thomas-led college trips to the East Indies, offering her work as a professional photographer.
In 1972, solitary student Hannes, Enzo Brumm, lives in a shared student housing near the campus, but spends most of his free time reading at the botanical garden near the gingko tree. One of his housing partners, Gundula Marlene Burow, researches the interplay between plants and humans, while Hannes claims indifference toward natural studies due to his rural upbringing and the farm work he endured in youth. As he develops feelings for Gundula, he tries to connect with her through Goethe's Metamorphosis of Plants, but she rebukes him for his lack of knowledge. During a campfire with Gundula and friends, she questions whether he would have sex with her since he’s supposedly still a virgin, to which a confused Hannes denies. Gundula leaves for a college trip, leaving him responsible for her research, which includes watering her plants and a purple geranium connected to an activity sensor. Hannes’s loneliness draws him closer to the sensor-equipped plant; by refining the sensor, he enables it to open the small gate of the residence. But a postcard from Gundula announcing her relationship with Peter leaves him shaken.
