A New Horizon is a mission in Ghost of Tsushima in which, after freeing Lord Shimura, you will be required to reacquire Castle Shimura, which lies under the control of the Mongols. In this mission, Jin will have to ride with his uncle, Lord Shimura, and fight the Mongols to reclaim their home.
Ghost of Tsushima A New Horizon
After completing Shadow of the Samurai, a long cutscene will play. Once it is completed, head straight down the path, through the bridge, and towards the next checkpoint. Go to Lord Shimura and speak with him.
Head to the stables, though you can also check on your allies by speaking with them, which is optional. Once you mount the horse, head out the gates and follow the path ahead with Shimura.
Eventually, you’ll reach the Old Togo Rice Field, there will be a Mongol patrol here. Deal with the patrol and head back on your horses. Once you reach Fort Ito, defeat the Mongols here.
Once you’re done, talk to Yuna and head to the lighthouse and a cutscene will play. Climb to the top of the lighthouse with Lord Shimura.
After you reach the top, another cutscene will play and Lord Shimura will tell you to return home to claim your father’s armor, recruit the peasants of Yarikawa, while he will petition the shogun for reinforcements.
He will also instruct you to find a pirate named Gora in Umugi Cove who owes Lord Shimura a debt.
After the cutscene ends, you will be next to your horse and Yuna. Head to the warrior monk named Norio and a cutscene will play.
Follow Norio to the pit, and then lead him towards the northern gate and exit the place and another cutscene will come into play in which Norio will tell you that the monks will help your cause.
Once the cutscene ends, your A New Horizon mission will be completed,