Prah Mantoos was leader of a group of pilgrims who, in 2151, were on their way to witness a protostar that emits an energy burst every eleven years, which the pilgrims called the Great Plume of Agosoria.

Jonathan Archer invited the group aboard the Enterprise NX-01 for a tour and dinner and to witness the Plume aboard his ship. Unknown to anyone else at the time, Suliban agent Silik was among Mantoos' group. (ENT: "Cold Front")