Chi Mu, a young man from the modern world, travels to the Sabison grasslands and is reborn as River Kid, a subadult male lion doomed to a tragic fate in a documentary. Facing the slaughter unleashed by the grasslands' tyrannical Exile Alliance, the old lion king Gap-Tooth dies fighting in a bloody battle, and the pride falls apart. Determined to defy fate, Chi Mu uses human intelligence and modern training methods to awaken his potential rapidly. Fighting for survival alongside his sister Kelly, he sets ambushes to lure enemies into traps, cuts off their tails and avenges old grudges, outwits the scarred villain, and gathers the fierce but good-natured Tony and the exceptionally gifted Xiao Ka as powerful allies. Together, they establish a new pride, the West Street Pride. Witnessed through livestream cameras operated by human streamers, a legendary lion king possessing both overwhelming strength and extraordinary intelligence rises through bloodshed and revenge to restore the glory of West Street!