United Cube Concert – One (Korean: 유나이티드 큐브 원) was the second domestic concert of South Korean music label Cube Entertainment in 2018. A total of 33 Cube artists performed, including Hyuna, Jo Kwon, BtoB, CLC, Pentagon, Triple H, Lai Kuan-lin, Yoo Seon-ho and (G)I-dle. The concert took place at KINTEX in Seoul with an audience of 8,500 people.

Psychological thriller musical based off a bestselling novel of the same name, tells the story of a classical composer who witnesses a murder one day and realizes that committing murder allows him to compose better masterpieces.