Walkthrough. All Bonus Objectives, Intel.
A mission of two parts.
First we're given a Mastermind, and have to possess enemy units and use them to remove the Watch Towers so we can possess the Barracks and train an Engineer. We do that, and then send the Engineer to capture the objective building.
In part two, we're given a seemingly large strike force. But you'll find it quickly amounts to nothing if you just charge in expecting a win. Instead, we slowly move the Devastators in on the base, destroying on structure or unit at a time. Meanwhile our other forces are eliminating any units that come out of the base.
After a short while, the base is done for. Our Mastermind is still alive so we get the Bonus Objective.
Mission accomplished!