On a tiny planet inhabited by beings made from natural materials, the original Guardians created a small Sun and Moon to bring light and harmony to their realm and traveled using massive temple-like creatures. In today’s world, the day and night inhabitants coexist peacefully despite their inherent differences. However, lurking in the shadows is Necross, a disgraced Guardian of the Sun who was once defeated by the brave warrior Xolal. He patiently waits for a chance to engulf the world in darkness once again.
In the present timeline, apprentice Guardians Sohone and Leeyoon are on the verge of stepping into the roles of Guardians of the Sun and Moon, taking over from their mentors Xolal and Yule. During the induction ceremony, the Sun embraces Sohone, but in a surprising twist, the Moon chooses a young and inexperienced Mune, breaking Leeyoon’s expectations.
Seizing the moment, Mox, Necross's mischievous servant, informs his master of Xolal's retirement, setting the stage for Necross's next sinister move to steal the Sun. After the ceremony, Xolal and Yule pass on vital knowledge to their successors before their transformations into a statue and a glowing tree, respectively. That very night, Necross unleashes Pale Snakes to taint Leeyoon's spirit, aiming to create discord between Sohone and Mune. Concurrently, Mune faces challenges in mastering the Temple of the Moon, while Necross plots to hijack the Sun with the aid of Mox and his ally Spleen. This onslaught plunges the world into night, leading to Mune’s banishment from his community.
Determined, Mune teams up with Sohone and a wax girl named Glim to track down the stolen Sun. Their journey takes them to the Great Blue Hole, a lake that serves as a gateway to the depths below, where they encounter Phospho, a former Guardian of the Moon. Phospho once held great power but, burdened by his past failures, gave up his role. He guides Mune and his friends to the entrance of the Underworld before disappearing.
As the situation intensifies, Leeyoon steps into Mune's role within the Temple of the Moon but finds himself unable to manage it. Consequently, as the Moon begins to decay, the Temple spirals into chaos and tumbles into the Underworld—where Mune, Sohone, and Glim find themselves. While Mune and Glim work together to stabilize the Moon, Sohone descends further into the Underworld in hopes of retrieving the Sun. Mune discovers that he can soothe the Temple of the Moon by harnessing his inherent powers, igniting a flicker of hope in Phospho, who watches from afar. Leeyoon acknowledges Mune's true potential as the Guardian of the Moon, expressing regret for his earlier dismissiveness.
With determination, Mune and Glim venture into the Moon Quarry, a mystical location unveiled by Yule just before his demise, to forge a new Moon. Their bond deepens as they face trials, while Leeyoon reconciles with Mune, recognizing his rightful place as the Guardian.
Upon completing their mission, Mune and Glim reunite with Sohone in the World of Darkness, where they confront Pale Snakes attempting to corrupt him. Just as all seems lost, Phospho heroically intervenes, sacrificing himself to save Sohone and vanquish the Snakes. Now rallying together, Sohone, Mune, and Glim confront Necross and his followers, all while Glim courageously revives the Sun, albeit at the cost of her own form.
In a dramatic climax, as Necross prepares to obliterate Mune and Sohone, the Sun and Moon converge, bestowing their incredible power upon the two Guardians. Mune taps into his liquid Dream powers, rendering Necross into a peaceful slumber and revealing the malevolence of a Pale Snake that had been corrupting him. With this confrontation, Necross is restored to his original state and turned into a statue, allowing the Underworld to blossom into a paradise.
In the aftermath, Mune and Sohone reclaim the natural order, restoring the paths of the Sun, Moon, and their sacred Temples. With newfound strength from the celestial bodies, Mune brings Glim back to life, granting her the ability to maintain her form amidst varying temperatures. Their story culminates in a tender moment as Mune and Glim share a kiss before embarking on adventures aboard the Temple of the Moon, ready to explore the wonders of their world together.
