The Lost Patrol

After completing Semper Invicta, talk to Paladin Danse to start this quest. Marker leads you to eastern side of Commonwealth. This is Super Mutant Territory so don't attempt this unless you are properly leveled and equipped. Upon reaching the quest point, you have to locate the distress signal.

Tune in your Pip-Boy to the distress signal. You'll get an indicator on the top left corner of your screen showing the Strength of the signal. You might also encounter a Legendary Raider in the area. First, head to the large building along the way to mark the location of Med-Tek Research in your map. Head to the south and you'll find a destroyed house where the remains of the recon team is found. There's a first aid kit here as well as an advanced safe.

The other Power armors are useless since they're burned out. You can loot the body of Knight Varham then pick up the distress transmitter. Pick up the holotape from his body and play it. A new location will be added to your map. As an additional objective, you'll have to report to Paladin Danse.

After reporting to him, continue to the National Guard Training Yard marked in the map. There are two auto-turrets installed on the roof of the armory so destroy them. The door to the Armory is an Master level so don't bother with it for now. You'll receive another distress signal. Tune in to that signal so you can track its source. (For the notable loots and points of interest in this area, refer to this location's page.

Grab them then enter the National Guard Recruitment office. Once inside, prepare for an ambush of ghouls, including a Legendary Feral Ghoul Reaver. Loot their bodies and grab the Short Assault Rifle on top of a container near the terminal. There is also a green trunk in the corner of the room beside the desk that contains 3 Fusion Cores.

There is an Advanced Wall Safe in the corner of the room in the second floor with the collapsed floor. In the second floor office, you can get the National Guard Officer's Password from the desk. This is the password that will allow you to access the terminal below. (This is optional and needed only for the complete Exploration of the area; not a part of the current quest progress)

Your objective is just on the ground floor, in the barricaded room. You'll find the corpse of Knight Astlin there. Pick up the transmitter and loot her body. Play the Astlin's holotape to learn your next destination to the Revere Satellite Array. You can go there immediately if you want or you can explore the Barracks section of this area. You can do that by using the Officer's Password you can get from the desk in the second floor. For more information about the Barracks area, refer to the National Guard Training Yard's Location page in this guide.

When ready head to the Revere Satellite Relay. When you're near, you'll receive another distress signal. The array is overrun with Super Mutants so be careful not to head there carelessly. There's also a very sturdy Super Mutant Suicider that will keep chasing you around and will blow himself up if he catches up to you. One good way to clear this area is to activate the combat sentry in the Robotics Disposal Ground. The satellite relay is within its range so you can send it to clear the area out of hostiles (or at least minimize the threat)

After clearing the area, find a shack connected by catwalks in one of the radar dishes. Loot Scribe Faris' equipment and the distress pulser beside him. Playback his holotape to update your quest objective. Your next destination is Recon Bunker Theta further north.

When you reach the area, interact with the terminal. You should already have the access code to unlock the bunker. Talk to Paladin Brandis and you’ll have a speech check. As you go through the conversation, you can give the Paladin the holotags of his fallen comrades. You can attempt to persuade him to rejoin the brotherhood.

After the mission objective is updated, you can now loot whatever is inside the bunker. Return to Paladin Danse in the Cambridge Police Station and report to him to complete the mission.