The original NCT sub-unit, NCT U, is back after their initial debut in 2016 with the dreamy, nostalgic ballad “텐데… (Timeless)” for SM Entertainment’s SM Station. Released January 12, “Timeless” allows the group’s vocal line—consisting of members Doyoung, Jaehyun, and Taeil—to show off their dynamic ranges, plush harmonies, and effortless high notes.

In the week building up to the song’s release, SM Entertainment shared footage online from past SM Rookies shows in a series called NCT.zip. SM Rookies is the name for the group of known trainees who have yet to officially debut at SM, but in the past have held concerts and a large majority of the members have gone on to debut officially within NCT. The videos include an over-the-top adorable cover of “Under the Sea” from The Little Mermaid as well as the poignant, heart-breaking “Timeless.”

Prior to their debut all together in NCT U, the members performed this song on stage at their SM Rookies showcases and kicked down the doors to every fan’s heart. It quickly reached a mythical level amongst NCTzens, especially for those who biased a member from the vocal line. Now that they’ve debuted within NCT and have been active for almost two years, the members returned to their roots to share a song that’s been beloved within the fandom for a long time and to show how far they’ve come.

When speaking about “Timeless” in a video on V LIVE, the members all agreed that it’s “the song that all NCTzens would know,” saying: “[Timeless] is a short title but has a big impact.” The members also shared that they have been singing the song together since they were trainees five years ago, making it a track that is just as important to them as it is to the fans.

It’s easy to see why this song has wedged itself within the pages of NCT history; it really caters to each member’s strengths. Doyoung’s voice is fragile and expressive, and he carries the song’s message of agony over losing a lover very well. Taeil is able to hit high notes that can make a listener cry, all with an incredible amount of power and clarity in his tone, and Jaehyun’s lower register complements the other two’s soaring vocals in a grounding, earthy way—especially when he harmonizes with Taeil as he hits an incredible high note. It is a masterclass in ballads and how to perform them.

Besides being a point of pride and nostalgia for NCT and NCTzens alike, the members also shared their reasoning for officially releasing the song as their contribution to SM Station. “We hope many people will feel healed from this song. We also feel healed listening to the song,” Jaehyun confessed. “You guys need to feel healed. You guys need to be warm and not lonely, and you guys should be with us.”

So take a moment to heal and gain a bit of NCT’s perspective with “Timeless.” After the first listen it may be hard to stop—don’t say we didn’t warn you!