This is a specialist mission to rescue Grace Armstrong, a very skilled sniper, who is trapped in the belltower of the Lamb of God Church. Upon arriving at the church, you’ll find her trying to fend off a small cultist attack. Help her take out the cultists then join her on the rooftop by climbing up the ladder on the side of the church. Talk to her to start the mission. After talking to her, you’ll have to defend the church from three sides. Pick up the semi-automatic sniper rifle on the ramp of the belltower and use it to pick off the enemies from the marked directions.
Prioritize cultists that are desecrating the graves. The objective list on the upper left of your screen represents the remaining “health” of the graves as they’re attacked by the cultists. More enemies will arrive by trucks. Be careful of the enemy snipers and flamethrower units as well. You can’t stay on the roof for long since the enemies may get too close and unreachable in your line of fire. You’ll have to go down and engage them in close-medium range while Grace provides covering fire from the belltower. Keep killing them as they come until their Assault is fended off successfully.