isolate_single_character_effect

isolate_single_character_effect = {
	add_character_flag = {
		flag = blocked_from_leaving
		years = 5
	}
	add_character_modifier = {
		modifier = isolating_modifier
		years = 5
	}
	involved_activity ?= {
		if = {
			limit = {
				OR = {
					activity_host = prev
					is_required_special_guest = prev
				}
			}
			invalidate_activity = this
		}
		else = {
			prev = { remove_from_activity = involved_activity }
		}
	}
}

As written in game/common/scripted_effects/00_decisions_effects.txt.