Ulla is a sensitive and principled 10th-grader in a small East German town. When Winfried falls in love with her, he adopts her passion for protecting the environment. One day, they discover that an illegal trout farm and weekend home are being built in the middle of a conservation area. Ulla tries to stop the project and gets her classmates involved. Winfried is in a difficult position because it is his father, the powerful director of a company, who is responsible. As they meet resistance from officials, the others gradually give up the fight to save the local nature reserve; but not Ulla, who is left to deal with the consequences. BIOLOGY! was one of the very few East German films that dealt with protecting the environment. This topic was taboo in the GDR, where all data on environmental demage was classified information. Nevertheless, grassroot activists—often under the umbrella of the church—represented a small but vigorous environmental movement.