Maine author Tess Gerritsen claims Warner Bros. owns the film rights to her 1999 novel “Gravity” but has not paid her the 2.5 percent of “net proceeds” – at least $10 million – due under the original contract. At the heart of her lawsuit is the contention that the film was based on her book, so here’s a look at both:

THE FILM

Main characters: Dr. Ryan Stone, a female medical engineer on her first space shuttle mission, with veteran astronaut Matt Kowalski

Setting: Space and space shuttle

Main plot device: The shuttle is destroyed by satellite debris, leaving the two tethered to each other in space. (Gerritsen claims she wrote a scene involving a deluge of satellite debris and gave that scene to New Line Productions, now part of Warner Bros.)

THE NOVEL

Main characters: Emma Watson, a research physician, on her first mission to the International Space Station. Her estranged husband wanted to go into space, too, but was grounded because of a medical condition.

Setting: Space, a space shuttle and a space station

Main plot device: Contagious microbes infect the space crew. Later, a rescue shuttle crashes.