Siglo 26, la humanidad se ve amenazada ante un conjunto de alienígenas denominado "El Covenant". Serie basada en el aclamado videojuego Halo y su protagonista, el spartan John 117(Jefe maestro).

Former special-forces soldier John Gold is given the opportunity to bring Sean Teague - the man who betrayed his team on their final mission in Eastern Europe several years ago - to justice. Gold would cheerfully see Teague dead, but he is convinced to help transport him to a military prison to pay for his crimes. Along the way, Gold will have to fight off Teague's team who are attempting to extract him, as well as a sniper seemingly hell-bent on killing Teague before he can be secured.

Una unidad militar de élite se encuentra con una entidad sobrenatural, conocida como The Elder Gods, que los obliga a luchar contra un ejército de otro mundo.

En un futuro cercano, el entrenamiento de un grupo militar de élite se convertirá en una lucha por su supervivencia al enfrentarse a unos sofisticados robots de guerra.