Beginning one month after the original Trails of Cold Steel, the game's events take place largely concurrently with the final chapter of Trails to Azure. Rean Schwarzer wakes from a month-long coma he fell into after unwillingly escaping from Trista at the end of the previous game. He makes it to his hometown of Ymir with the assistance of bracer Toval Randonneur, but Rean quickly finds himself and his loved ones caught in the crossfire of the war. Rean's opponents are the Noble Alliance, which has partnered with the Imperial Liberation Front from the previous game, as well as Ouroboros - a recurring group of antagonists in the Trails series. Students from Thors Military Academy, including those from Class VII, have been scattered across the country, so Rean resolves to find his classmates, put an end to the civil war, and save those he cares about.
The gameplay of Trails of Cold Steel II is similar to the first Trails of Cold Steel game, being a traditional Japanese role-playing video game with turn-based battles. Game progression is no longer tied to the school schedule structure of the original, with the game now centered around traveling the world rather than attending classes. If the player has a completed game save file from the prior game, it has an effect in Cold Steel II, with certain events and dialogues playing out differently based on choices and relationships built in the first game.
Source: Wikipedia, "The Legend of Heroes: Trails of Cold Steel", available under the CC-BY-SA License.