This achievement is awarded after completing the following missions in Sequence 5 with at least 50% synchronization:
Memory 1 - A Boorish Man
Memory 2 - A Trip to Boston
Memory 3 - Boston's Most Wanted
Memory 4 - Lying Low
Memory 5 - River Rescue
Memory 6 - The Hard Way
For those of you going for
The video below is from ZasterModa123's solution and contains a complete walkthrough of sequence 5. The video does not belong to me, and I do not take credit for it.
Sequence 5 begins at 9:41 in the video.