In the Jingding era of the Southern Song, war rages on every side. Mongol horsemen advance south, and Jiangnan trembles in the storm.
A young man possesses the peerless art of Tianyuan calculation. By chance, he is swept into the murky tides of the martial world. He fuses mathematical principles with martial arts, uses the Eight Trigrams to find his bearings, and reads people's hearts to predict their moves, forging a martial path unique to Tianyuan amid flashing blades and swords.
He ventures into the northern deserts and across the Western Regions before returning to Jiangnan. He witnesses the court's treachery, endures the martial world's feuds, makes sworn friends, and meets the women he loves, but also tastes betrayal and parting.
He once meant to calculate every matter under heaven and command his own fate. But amid the tide of a world in chaos, he finally realizes that the Heavenly Dao is unpredictable and the human heart impossible to read. Tianyuan was never about calculating everything. When the nation falls and families are lost, it means holding fast to the principles in one's heart and moving with the greater tide.
A song of a young hero, capturing the chivalrous spirit and tender feelings of the Southern Song martial world, and the love of country and home shared by those living through troubled times.
