The film follows the young cat demon Xiao Hei after his home is deforested by humans and he must find a new one. He runs into a group of other fey creatures led by the formidable Feng Xi, who have also lost their homes and take him under their wing with dreams of reconquering the land they say is rightfully theirs. However, they run into a human "Executor" known as Wuxian, who is tasked with defeating Feng Xi. Their tussle leads to Feng Xi and company having to abandon Xiao Hei and inadvertently leaving him at the mercy of Wuxian, stranded on an island. The two go on a journey back to the mainland, with Xiao Hei learning to control his abilities as well as forming his own thoughts on whether or not he's on the fey's side or the humans. Meanwhile, Feng Xi is not all he appears to be...
The movie received a Japanese dub distributed by Aniplex simultaneously with the Chinese version, and an English dub by Play Big and distributed by Shout! Media released in 2021.
This film contains the following tropes:
- All Myths Are True: All forms of Chinese mythical creatures exist in this film, and when interacting with civilians, they're treated like normal people.
- Bait-and-Switch: In one scene, the child apprentice MaoMao finds his master Min unresponsive with his belongings scattered on the floor. The audience and the poor kid are led to believe that Min was killed in a struggle with Feng Xi, given the latter's suspicious comment about taking something of his—but just as the apprentice is about to mourn the loss of his master, Min simply wakes up. His powers were stolen, but he'll be fine.
- Barely-Changed Dub Name: The Japanese dub uses the same characters for all the cast's names but changes them to Japanese pronunciation. The English dub by contrast transliterates everyone's name except for Xiao Hei's (who is merely referred to as "Hei").
- Continuity Cameo: Niepa, who shows up in the last few episodes of the main series Season 1, appears in this movie as a nameless cat fey that Wuxian deals with in his introductory scene. Some of the future Spirit Hall regulars like Fu also show up during the climax, and the main cast of the web series make a small cameo during the credits sequence.
- Daydream Surprise: While traveling with Wuxian and resting for the night, Hei begins to imagine his only night with Feng Xi's group, and the warmth and familiarity he experienced at their campfire. When he reaches for the meat his hallucination offers him, he's met with Wuxian's expressionless face and a stick of bland poultry.
- Dine and Dash: After finally getting to the mainland, Wuxian offers to treat Hei to a meal. In a rare case of this trope, Wuxian really meant to pay for their food; but being short on cash, unable to pay digitally without a working smartphone, or able to bargain a jade coin for it, he just up and leaves.
- Doit Yourself Theme Tune: "Xin", the ending theme of the movie, is sung by Ah Suo, voice actress of many bit characters and small characters in the series (most notably Bidiu, the original web shorts' Team Pet).
- Driving Question: Whether humans and elfin can truly coexist. Many elfin have been able to live in human cities and civilizations, but only because they have to disguise themselves as humans and can't exist as their normal selves. Elfin who dislike that practice have to live in elfin-only spaces or decide to strike back and hurt humans.
- Foreshadowing: When Wuxian and Hei are in the middle of a raging storm in the ocean, all seems lost until the pair is saved by a force field surrounding them just before a wave crashes into their raft. The force field is really Hei's true power, Domain, manifesting itself unconsciously.
- The Foreign Subtitle: The movie, at least in its distribution by Toho, gets the subtitle Boku ga Erabu Mirai (The Future I Choose) in Japan.
- Found Family: Double subverted. Hei thinks he's found this with Feng Xi's group, but while they do like him Hei was only ever with them for one day. He truly receives this when he starts bonding with Wuxian and slowly accepts him as his master and father figure.
- Green Aesop: A lot of the elfin's problems with humanity boil down to them destroying the natural world and uprooting them from their homes. Hei begins hating humans because the forest he used to live in was bulldozed over, and Feng Xi and the old elfin both mention that their homes were destroyed the same way. In Feng Xi's case, he wasn't outright displeased with humans and even liked some of the things they brought, but it wasn't until industrialization hit that he really started despising their ways. Human negligence can also be seen in background details, like Hei mistaking a plastic bag for a spirit and abandoned factories and homes in isolated areas.
- Humans Are Bastards: The other elfin see humans as such since they feel wronged for them stealing their homes away. Luo-Xiao Hei initially agrees with this view, but after spending time with Wuxian, he starts to change his views to be more gray.
- Living MacGuffin: Xiao Hei turns out to be this in the climax. His ability, Domain, allows him to take anything into his spiritual space and even expand it. Feng Xi came after Hei primarily to steal this ability and move Longyou into a spiritual space for elfin to live in.
- Long Haired Prettyboy: Powerful characters often have the longest hair in the movie. Wuxian, Feng Xi, and Xuhai are among the most prominent examples.
- Meaningful Echo: Xiao Hei's only night in Feng Xi's company includes a scene of him sitting around a roaring campfire, eating delicious meat and getting a headpat from him, encapsulating the feeling of home that Xiao Hei most desired. The scene is so strong that he still daydreams about it weeks after he's left. The scene is subtly mirrored when he's traveling with Wuxian on the mainland; while the fire is meager, all they have to eat are small fish, and they've been at each other's necks for a majority of the journey, Wuxian giving Xiao Hei a headpat for the first time shows the audience the growing bond between them that neither realize is forming.
- Mythology Gag: One can hear a little kid singing "Goodbye Meow" in the background of one mainland scene.
- Power Parasite: It's noted that elfin can train to steal other's natural abilities, but it's a forbidden practice. Stealing abilities that are tied to one's affinity, like telepathy or moving metal, is less frowned upon as the ability can just be gotten back with training, but stealing abilities that are directly tied with one's spiritual energy is dangerous since it could kill them. Xiao Hei's Domain ability is the latter.
- Prequel: The movie serves as a prequel to the animated shorts. The credits sequence shows what the main characters of the web series were doing at the time, confirming that this film takes places only a few years before the main story.
- Unusually Uninteresting Sight: The most that normal people will do when they see the creatures is take pictures, but only if they look relatively harmless or humanoid. They start truly freaking out when the elfin start using their powers.
- Training Montage: Gets interspersed with a traveling montage while Xiao Hei and Wuxian explore the ocean and the mainland. It mainly focuses on Xiao Hei learning to manipulate Wuxian's metal strips.
- Traintop Battle: Feng Xi and Wuxian have one during their first reunion on the mainland. It was preceded by a battle inside the train with Yezi and A'he.
