K-Pop superstars A.C.E ("Adventure Calling Emotions") honed their synchronized moves and hyped-up vocals on the streets. The boy band, signed to the Beat Interactive label, regularly put on outdoor shows in the run-up to the release of their first single, 2017's "Cactus"; the quintet would post the shows to their YouTube channel, which also features covers of K-Pop contemporaries like BLACKPINK (whose "Stay" gets a tender reading from the group) and K.A.R.D (whose "Don't Recall" gets a funky reworking assisted by up-and-comer fla4free). Their YouTube channel has helped their fan base grow around the world — and become big enough to warrant conventions devoted just to A.C.E and its listeners despite having only a handful of songs under their belt.

In late 2017, A.C.E leader Jun and vocalist Chan were contestants on The Unit, a show that focused on rebooting K-Pop idols' careers. At the same time, rappers Kim Byeongkwan and Wow, as well as vocalist Donghun, competed on Mix Nine, a K-Pop talent search. Early in 2018, Chan left A.C.E to be in The Unit's group UNB, turning A.C.E into a foursome.

A.C.E released their first EP, A.C.E Adventures in Wonderland, in June 2018; a showcase of the group's musical and stylistic diversity, it features their 2017 singles — the pulsing, dubstep-inspired "Cactus" and the percolating "Callin'" — in vocal and instrumental form, as well as the trap-pop/EDM hybrid "Black and Blue," the shimmering "Take Me Higher," and the piano-led ballad "5TAR (Incompletion)." With UNB set to break up in the winter of 2018, Chan returned to the fold over the summer, restoring A.C.E to quintet status — just in time for their first world tour. Kicking off in Buenos Aires on Nov. 16, the A.C.E World Tour [To Be an Ace] will hit Argentina, Chile, and Mexico before landing in the U.S. on Nov. 24.