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.

Zerobaseone comprises the nine winners of Mnet's idol survival program, "Boys Planet" -- Ji-woong, Zhang Hao, Hanbin, Matthew, Tae-rae, Ricky, Gyuvin, Gun-wook and Yu-jin -- and made its debut in July with "Youth in the Shade."

The competitors-turned-teammates said a deeper connection with each other was what they achieved in working together on their past album.

"We've become a (closer) team. It's exciting when we sync up perfectly when dancing," Ji-woong said, adding, "We spend a lot of time talking with each other, and although I'm the oldest, I learn a lot from the other bandmates."

The group's debut was historic, with its debut album racking up 1.24 million units in sales on its first day, making Zerobaseone the first K-pop group in history to nab a million-seller title on its debut day. Recently, the album sales surpassed the 2 million mark, another record set by a K-pop group's debut album.

The nine-piece act bagged its second million-seller title with its new album, even ahead of the EP's Monday release. According to the band's agency, WakeOne, "Melting Point" reached over 1.7 million units in pre-order sales last month, surpassing the 1.08 million logged by "Youth in the Shade."

Living up to their short yet star-studded career was the priority for the group's members.

"Rather than feeling pressure, we're working hard (on our) performances and music to prove ourselves," Tae-rae said.

"We said during our debut showcase event that we wanted to win the New Artist award, and we did, all thanks to Ze-Rose. I hope we win more, and we'll work harder and devote ourselves humbly so that time will prove we were the rightful winners of the prizes," Ji-woong added

Monday marked the 200th day since Zerobaseone was officially put together. Celebrating the special day, Gun-wook closed the event with a heartfelt message.

"We didn't waste a single moment of the past 200 days and gave our everything. I feel like I made a new family this year. The eight bandmates are my family and I hope to spend every moment with them with no regrets."