Million-seller rookie group Zerobaseone is taking the next step in its youthful journey with its second EP, "Melting Point."

The new album came out Monday afternoon, marking the group's swift return to the K-pop scene four months after making its debut in July.

In their last album, "Youth in the Shade," the boys sang about how the uncertainties in their endeavors made their youth shine. In the new album, the boys overcome ambivalence and gain confidence in themselves.

Nabbing the million-seller title upon their debut, the rookies' next goal is to make hit songs.

"We've been gratefully nicknamed the 'mega rookies' since debut and worked hard to live up to the title. Taking another leap, we hope our song becomes a 'megahit,' and hopefully, (we can) become the icon of fifth-generation idol groups," said Zhang Hao, one of the group's Chinese members, during a press conference held in Seoul on Monday before the album's release.

Fronting Zerobaseone's new album is "Crush," a powerful mixture of drum-and-bass and jersey club rhythms, which conveys through its lyrics the newfound determination of the group's nine members.

"We came this far and stand here right now all thanks to our fans, Ze-Rose. Like the lyrics 'You save me' say, we sing of our firm resolution to become stronger for our fans who have made our dreams come true, and to protect them no matter what," explained the group's leader, Hanbin.

The album's four side-tracks -- "Melting Point," "Take My Hand," "Kidz Zone" and "Good Night" -- share the different emotions and wishes the group's members discovered on their K-pop journey.