From the About page: "Founded in 1884, The League of S.T.E.A.M. (Supernatural and Troublesome Ectoplasmic Apparition Management) is a group of monster hunters and paranormal investigators, dedicated to the study, capture, and elimination of all manner of cryptozoological creatures and supernatural threats. The team is comprised of skilled adventurers, inventors, hunters, and scholars. Together, they're prepared to handle any type of paranormal situation."
Note: Producers captioned first two seasons, but did not caption the third season.