Immortality follows Chu Wanning, the number one grandmaster in the world, and his disciple Mo Ran in a story about overcoming all odds to protect humanity. Chu Wan Ning is an elder with immense spiritual powers. He is an upright and noble man who bears the responsibility of defending the mortal realm. Mo Ran is one of his disciples. Mo Ran is a gifted cultivator with a good heart but due to his sufferings at a young age, he is unruly and often opposes his master Chu Wan Ning. An accident causes Mo Ran to remember an inexplicable memory where Mo Ran and his martial sister dies because of Chu Wan Ning's indifference. With a renewed grudge directed at Chu Wan Ning, Mo Ran begins to secretly guard against Chu Wan Ning and even engages in actions that would hurt his master.