Defend The Castle Main Story, Minutmen Quest

1. Travel to the Castle

The Institute is preparing to attack the Castle to try to crush the Minutemen before we can build up enough strength to strike them. I need to help defend the Castle before it's too late.

Go to the Castle and talk to Ronnie.

2. Build defenses

3. Defend The Castle

4. Speak to Ronnie Shaw

The Institute attack on the Castle has been defeated. Now we can think about turning the tables and taking the fight to them.

5. Talk to Preston Garvey

Next / new quest is The Nuclear Option (Main Story, Minutmen).