ASTERUM may be a brisk 2 tracks, but it's enough to introduce the world to PLAVE for the first time. This debut single album is named after the world that bridges the group's own (Caelum) to ours (Terra), hence its themes of hope and new beginnings.

Title track "기다릴게 (Wait for you)" is a soft rock track about waiting to convey one's growing feelings for someone else. Its slow style makes for a sentimental debut with a hopeful tone.

The B-side, "Pixel World", is a fun little synth-pop tune about making the titular world together and having fun. It shows a playful and exciting side to PLAVE, featuring a lively atmosphere and catchy melodies.