Assassin's Creed 3 Walkthrough Part 25 – Sequence 5: Lost Son's Return, River Rescue

Lost Son's Return
Back in Davenport there are a few things that need to be attended to. Now you can just run over there (swimming does not work thanks to the sheer cliff with no hand holds). You will find the marker for the next memory to the West of where you arrive. You will find Achilles waiting inside the living room to the left of the Front Door (to the right if you went through the front door). After a quick cutscene a man comes to Davenport and starts banging on the window.

River Rescue
With the man banging on the window, head outside via the front door. Turn to the left and talk with him. This starts Godfrey running off. Follow him as best you can away from the house and toward the nearby river. Follow him until you get a cutscene.

Optional Objective:
Do not touch the water while rescuing Terry

Start off immediately out onto the water. If you just want to complete the mission, you can go right in for the rescue. For the optional objective you must be fast. Head out onto the outcropping of snow in the river and use it to reach the log on the center of the river. Turn to the left and chase after Terry this as Connor is led back to the left bank. Keep the chase up, jumping from stone to stone along the river's edge. Never leave the river if you want to keep up with Terry.

Dash onto the log that is past the set of rocks that Connor had to run over. Just keep to the left hand bank until you see a tree reaching over to the right. Take it across quickly and keep to the bank of the river. Now you need to hurry and be careful.

This final part can play out one of two ways. You need to reach the log to save Terry but to complete the optional objective you cannot touch the water. You must get to the end of the branch and jump down as the log is in reach. If you mistime it then Connor will go into his Dive animation. Watch out for it. Dive when you first see the prompt to avoid failing this part of the mission and complete it successfully.