Infinity Train Season 4 - Duet (2020)

Ryan and Min-Gi are childhood best friends who want to become famous musicians someday. As they grow, they realize they may have different priorities in life. One fated night, the two reunite and talk about their future. Ryan and Min-Gi get into a disagreement and are invited to enter the Infinity Train, where they meet Kez, a floating magical service bell who will accompany them through their journey on the train. Follow the trio as they encounter the denizens of the train and attempt to make it back home.