This achievement is awarded after completing the following missions in Sequence 10 with at least 50% synchronization:
Memory 1 - Alternate Methods
Memory 2 - A Broken Trust
Memory 3 - Battle of Monmouth
For those of you going for
The video below is from ZasterModa123's solution and contains a complete walkthrough of the optional objectives in sequence 10. The video does not belong to me, and I do not take credit for it.