"The Equation" is the eighth episode of the first season of the American science fiction drama television series Fringe. The episode follows the Fringe team's investigation into the kidnapping of a young musical prodigy who has become obsessed with finishing one piece of music. Dr. Walter Bishop returns to St. Claire's Hospital in an effort to find the boy's whereabouts.

The first season of the American science fiction television series Fringe commenced airing on the Fox network on September 9, 2008, and concluded on May 12, 2009. It was produced by Bad Robot in association with Warner Bros. Television, and its showrunners were Jeff Pinkner and J.H. Wyman. The first season introduces a Federal Bureau of Investigation "Fringe Division" team based in Boston, Massachusetts under the supervision of Homeland Security. The team uses unorthodox "fringe" science and FBI investigative techniques to investigate a series of unexplained, often ghastly occurrences, which are related to mysteries surrounding a parallel universe. FBI agent Olivia Dunham is portrayed by actress Anna Torv, while actors Joshua Jackson and John Noble play father-son duo Peter and Walter Bishop. Other regular cast members include Lance Reddick, Jasika Nicole, Blair Brown, Mark Valley, and Kirk Acevedo.