A long time ago, the great Monkey King ruled and protected the land. Until one day, the Demon Bull King attacked and tried to destroy everything in his path. But the Monkey King was clever. He used his magical staff to trap the demon inside the Flower Fruit Mountain, forever. And the world has been safe to this day. But when fate leads MK, a noodle delivery boy, to find the Monkey King’s long-forgotten staff, his life spins into an epic adventure he could never have imagined. A new legend is born.
Teenage hero MK and his friends must save their city from the Demon Bull King, in the LEGO adventure inspired by classic Chinese stories.
According to Jeremy Adams, LEGO Monkie Kid isn't a direct representation to Journey to the West, as it would give the characters and plot more development for the show, and help people learn more about the Chinese novel.
This explains why most of the characters from Journey to the West have their names and/or history altered in the show.