A 9-year-old boy embarks on a secret adventure to visit his ailing mother at a faraway hospital — with his trusty new friends at his side. Lee Kyung-hoon, Park Ye-chan, Hong Jung-min, Park Si-wan, Ok Ye-rin, Lee Sang-hee, Yoon Kyung-ho, Gong Min-jeung Added on Netflix 2023-02-24.