Pokémon 3: The Movie: Entei - Spell of the Unown (try saying that five times fast) is the best of the early Pokémon movies. The film kicks off when the titular Unown, psychic Pokémon who become very powerful in large numbers, use their abilities to grant the wishes of a young girl who recently lost both her parents. When she wishes for a mother, Entei, a magical guardian summoned for her by the Unown to be her "daddy", kidnaps Pokémon lead Ash Ketchum's mother to give her one. Ash is in pursuit and it's up to him to save his mother and stop the Unown, whose powers are quickly growing out of control.
Pokémon movies don't tend to be great at giving the main cast character development. The first movie even went as far as erasing its events from their memories, probably as an attempt to stop it from conflicting with the series' canon. Instead they often give the character arc to another character, and in this case it goes to Molly Hale, the girl whose wishes are being granted. Over the course of the movie she has to come to terms with losing her parents, and accept that she can't just wish her problems away. It's hard for her, and initially she gets lost in the promise of the Unown to give her everything she wants or needs, but she learns to believe in herself. She (inadvertently) sets many of the events of the movie in motion, and the plot doesn't begin to wrap up until she learns the lesson of the film, but she isn't really an antagonist, and neither is Entei. This film doesn't really have antagonists. Molly herself makes mistakes, but they are understandable mistakes given that she's a child who has been given seemingly unlimited power. She manages to walk the line of being tempted by everything the Unown offer without becoming insufferable as a character. The film remembers that she is hurting, and has her act more from a sense of wonder and desire to stop hurting than a desire to hurt anyone. Entei is the closest the film comes to having a "bad guy" but even he consistently acts from a place of love and is governed by the same childish logic as Molly.
The Pokémon movies before Pokémon 3: The Movie had their good points, but both of them were missing something. Pokémon: The First Movie tried to tell a deeper story but failed, telling a pacifist message that didn't quite work in a series which revolves around battling. Pokémon: The Movie 2000 is a fun adventure, and its action is much improved over the first film, but it doesn't have the ambition of the movie which came before it. Pokémon 3: The Movie manages to take on the strengths of the series up to that point, and make them better. The first movie's desire to tell a story about people putting aside their differences to come together and grow with each other is told beautifully here. Just like the second film, there is a sense of adventure, and some strong action pieces on display. The fight between Entei and Charizard is some of the most dramatic battling in the Pokémon anime's history up to that point.
Pokémon 3: The Movie avoids the problems which came to plague the series after it. Pokemon4Ever was about an unambiguously evil antagonist attempting to capture a super cute and very powerful Pokémon for his own villainous ends. That movie did a pretty good job at telling this story, but unfortunately the series kept trying to tell this story afterwards. Way too many Pokémon movie boils down to basically just trying to be Pokemon4Ever again, with increasingly diminishing returns in terms of quality. Pokémon 3: The Movie on the other hand managed to avoid the increasingly noticeable rut that the series fell into afterwards. It doesn't rely on any overused plot points, and the characters are all well rounded characters.
Making a movie from an animated TV series gives the animators a chance to show what they can do with increased resources, and this film is no exception. As the power of the Unown starts to spiral out of even their control, their psychic energy crystallizes around them, and it makes for a beautiful sight on the screen. Seeing the town the movie is set in, and the building the action takes place in covered in psychic crystals is among some of the more striking sights in the series, like the fight between Mewtwo and Mew in the first film, or the villain's enormous flying machine in the second one.
Pokémon 3: The Movie: Entei - Spell of the Unown is everything a Pokémon movie can and should be. Rather than attempt to tell a story of good and evil, it shows sympathetic people attempting to get by in a world with creatures whose powers allow them to do great things. It manages to pull this off while still showing plenty of conflict between its characters, and showing off some great action; Pokémon doesn't need to be about a moustache twirling criminal attempting to take over the world to have high stakes. As a movie, it takes the basic message of the series "you teach me and I teach you" and puts it into practice over the course of 74 entertaining minutes. It's a stand out in its franchise, and even though 19 Pokémon movies have been released since, it still manages to be one of the best Pokémon movies ever made, and the best outright of the franchise's earlier efforts. It's not just that it avoided the faults of the other films. When it comes to Pokémon this movie just gets it.