The ruby

DSP Media announced the return of the group on October 16, 2018 on October 4. ^[2] Osen noted that the promo poster was different from the previous groups because it lacked any primary colors, and noted that the group developed and matured with each release, “adding different changes to each album.” Several other photos also noted a change in style. ^{[3] [4]}

“Oh! My Mistake ”was released along with the album on October 16th, Billboard called it“ an animating dance track that adds a new dimension to the band’s artistry ”as well as“ unusual ”and describing it as“ an 80s-style track ”. The magazine also said the video "brings audiences back to past years." ^[one]

The album debuted and reached 10th place on the Gaon album chart.

The album begins with “Oh-e-Oh”, a fun tropical song, and then the single “Oh! My Mistake ”, a“ weird ”retro dance track. “Story,” the third song, was called a “bizarre, retro synth pop melody,” and the last original song on the album “Love Clock” is a pop rock track about the passage of time. ^[1]