A New Horizon is a main story mission in Ghost of Tsushima after saving Lord Shimura.
Your task is to head north together with Shimura to eventually take back Castle Shimura.
Here’s a walkthrough of A New Horizon in Ghost of Tsushima.
Walk to the keep with Yuna
The quest begins automatically. Walk with Yuna to meet Shimura first.
Optional – talk to your allies
Before going to the stable, you can talk to your allies first. Masako, Ishikawa and Kenji will be around.
Head to the stables
Once you’re ready, go to the stables at the entrance.
Ride with Lord Shimura
Follow Lord Shimura using a hidden path to reach north.
Defeat the horseback Mongols
You will then come across a Mongol patrol. Take them all out.
Defeat the Mongol with the alarm
You will then reach a Mongol territory and you have to find the Mongol who is carrying the alarm.
Take out the Mongols who are guarding the alarm.
Head to the front gate
After clearing the entire area, go back to the front gate with Shimura.
Defeat the Mongols
You will be joined by Yuna and you have to defeat the incoming Mongols.
Head to the lighthouse
After the battle, go to the lighthouse with Shimura.
Climb all the way to the top and ignite the lighthouse.
Meet the warrior monk
After the cutscenes, talk to the warrior monk.
Exit the campsite through the north and another cutscene will load.
The quest ends here.