Set during the years between the "Rebecca" trial and the writing of Du Maurier's short story "The Birds", including her relationship with her husband Frederick 'Boy' Browning, and her largely unrequited infatuations with American publishing tycoon's wife Ellen Doubleday and the actress Gertrude Lawrence.

Before their eventual team-up with Scooby and the gang, bright and optimistic Daphne and whip-smart and analytical Velma are both mystery-solving teens who are best friends but have only met online - until now. Daphne has just transferred to Velma's school, Ridge Valley High, an incredible tech-savvy institute with all the latest gadgets provided by the school's benefactor, tech billionaire Tobias Bloom. And while competition is fierce among the students for a coveted internship at Bloom Innovative, Daphne and Velma dig beyond all the gadgets and tech to investigate what is causing some of the brightest students in school to disappear - only to emerge again in a zombie-fied state.

In the future, water has covered much of the Earth due to the effects of global warming, leaving the human race to live on neighboring floating cities. The orphaned Maia Mizuki, 15, just graduated from middle school and has already applied for employment in the elite Ocean Agency, part of the futuristic world government. Only the best, most intelligent, and physically fit students are eligible for admission.