4E Missions, or 4th Echelon Missions, are a new feature introduced in Tom Clancy's Splinter Cell: Blacklist. In this mode, players can earn additional currency by completing missions given to the player by Fourth Echelon members or captives aboard the C-147B Paladin. These missions, for all intents and purposes, work as side missions that can be played either alone (solo) or with a friend (co-op), either via Split-Screen or online though Xbox Live or PlayStation Network.