When a curious signal pulses through the shimmer, Queen Amalthea and her sisters are summoned to Roswell, New Mexico. Beneath the glowing sands, they discover a stranded alien named Zarnok, who has lost something precious-a golden ticket that grants him passage home through a cosmic portal hidden in the desert.
But Roswell is full of strange energy and watchful eyes. The mermaids and Zarnok must race against time, decoding ancient symbols, dodging nosy UFO hunters, and navigating a labyrinth of glowing tumbleweeds to find the lost ticket before the portal vanishes.
Along the way, Zarnok learns about trust, and the mermaids learn that sometimes, even stars get homesick.