The film, directed by Yasuhito Kikuchi, who also helmed the prior movie "Scarlet Bond" and a significant portion of the television series, unfolds as a poignant romantic tale. This new chapter introduces a love interest for Gobta, one of Rimura's key advisors, shifting the narrative focus from the protagonist. Despite Rimura's typically central role, his involvement here is more peripheral, acting as a diplomatic figure assisting Gobta's romantic endeavors. The story, set against a backdrop of palace intrigue, features moonlit encounters and a distinctive blend of humor appreciated by long-time fans. A compelling aspect of the film is its exploration of Yura’s backstory, with flashback scenes rendered in a distinct, more rudimentary animation style. This artistic choice harmonizes with the film’s cosmic and aquatic thematic elements, showcasing the visual dynamism expected from a theatrical release, particularly in its depiction of underwater action sequences.

The core premise of the anime revolves around Rimura Tempest, a seemingly ordinary Japanese man reincarnated in an alternative realm as a slime. This unique ability allows him to absorb the powers of diverse beings, culminating in his ascent as a formidable leader of a multi-species civilization. His extensive adventures involve conflicts with various mythical creatures, such as dragons, demons, and ogres. By the third season, Rimura actively engages in diplomatic efforts to foster alliances and construct his burgeoning nation. In "Tears of the Azure Sea," Rimura, often appearing in his human form, finds himself invited with his entourage to Celestial Emperor Elmesia's secluded island. It is here that they encounter Princess Yura, fleeing from adversaries, prompting Rimura and his companions to intervene.

For individuals unfamiliar with the "That Time I Got Reincarnated as a Slime" saga, the movie's title might suggest a narrative rich in unique, amorphous entities. However, the film diverges from this expectation, offering a more conventional anime plot. While the movie stands independently of the main series, its generic storyline might not fully captivate those without a prior connection to the franchise. The inclusion of new characters like Princess Yura and her pursuers, Zodon and Djeese, injects fresh dynamics, but the central focus subtly shifts. Gobta, traditionally a source of comic relief, takes on a more significant role as Yura's unexpected romantic partner, offering a fresh perspective on his character. However, given that the fourth season of the series is still ongoing, "Tears of the Azure Sea" ultimately functions as a supplemental narrative, a brief diversion for existing fans, rather than a pivotal new chapter compelling enough to draw in uninitiated audiences.