In this beginning reader graphic novel, two very different sisters find a common cause.Math-loving Nera and artistic Lucy live on the Moon, where they're often at odds. Both have round heads, each with a single antenna protruding from her forehead, though Nera is blue-skinned, while Lucy is green-skinned. Not even a shared eighth birthday present-a tiny Luna Fish they name Moona-can bring them together. At first neither child wants the new pet; then they both fight over it. Eventually, both sisters bond with Moona in their own ways, but Moona quickly outgrows her fishbowl. When the owner of a space aquarium offers to buy Moona and make her a star, Nera wants to sell, but Lucy balks. They flip a coin to decide. Nera wins; an angry Lucy stalks off. But once Nera visits the aquarium and sees how miserable the other animal performers are, she has a change of heart. The aquarium's owner refuses to release Moona, so Nera and Moona flee, and a high-speed chase across the galaxy ensues. Eventually, the sisters work together to put things right-though it's only a temporary truce. Bright, blocky artwork created with brush, ink, and Photoshop immerses readers in a fast-paced space-age adventure. A variety of panels, paired with accessible text laced with humor, demonstrate that even the most embattled siblings can unite when necessary.Outlandish science fiction fun for the younger set. (Graphic early reader. 4-6)