Kidd Summers is a female adventurer who appears as a major character in the animated film Lucario and the Mystery of Mew. Before her true identity is revealed, she first appears at Cameran Palace participating in the town of Rota's annual tournament to decide the Hero of the Year, disguised in traditional knight's armor. She and one of her two Weavile battle in the tournament, ultimately losing in the final round to Ash and his Pikachu. Following the match, she removes her helmet, revealing herself to be a woman.

Kidd is renowned as a world-famous, fearless, and thrill-seeking adventurer who has broken numerous world records. These records include the fastest circumnavigation of the world in a hot-air balloon, the deepest one-man submarine dive, and the longest independent space walk. Despite her accomplished and daring public persona, she was raised to be preppy, creating an interesting contrast in her background. Her physical appearance includes blue eyes and dark brown hair. Throughout the story, she is backed by a high-tech organization run by a commander named Lieutenant Banks, who provides her with advanced equipment. This includes a pair of sunglasses she uses to take photos, view map information, and maintain audio communication with Banks, as well as small exploration robots for gathering samples.

Her primary motivation in the film is research-based. She travels to the Rota region to investigate the connection between the mythical Pokémon Mew and the Tree of Beginning, also known as the Tree of Life. Initially, her methods are secretive and suspicious, leading to the implication that she might be an antagonist. For example, after slipping away from a ceremonial ball where she dances with Brock, she changes into her normal outfit and sends her two Weavile to place a tracking device on Mew. This mission fails due to the intervention of Ash's and May's Pokémon. Her motivations are later revealed to be professionally driven, as Banks's company was facing financial difficulties and the mission was intended to be a success. However, after discovering the fragility and natural beauty of the Tree of Beginning, she has a change of heart and decides to keep its location and secrets hidden from the public to protect the Pokémon environment.

In the story, after Mew takes Pikachu and Meowth to the Tree of Beginning, Kidd joins Ash and his friends on their journey to find them, with the help of the aura Pokémon Lucario. Throughout the perilous journey, she keeps in contact with Lieutenant Banks, transmitting information about Mew, Lucario, and the Tree of Beginning. Her role evolves from a researcher with a secret agenda to a key member of the group. At the Tree of Beginning, she is attacked by the red blob antibodies produced by the tree to keep intruders away. As she is being captured and consumed by one of these antibodies, she releases her Weavile from their Poké Balls to save them. She is later rescued thanks to Mew's intervention. Kidd also plays a role in helping Mew after it falls ill due to the gradual destruction of the Tree of Beginning.

Kidd's key relationships include her professional partnership with Lieutenant Banks and her deep bond with her two Pokémon. While her Weavile can be unruly and somewhat disobedient, she scolds them when they attack Mew but clearly cares for them greatly, as demonstrated when she prioritizes their safety over her own. She forms a temporary alliance with Ash and his friends, accompanying them on their adventure. At the conclusion of the film, after Mew and the Tree of Beginning are saved, Banks tells Kidd that she could make a fortune by selling the story of her adventure. However, she ultimately turns this down to keep the Tree of Beginning safe from commercial exploitation and tourism.

Kidd Summers demonstrates notable development throughout the narrative. She begins as a record-breaking adventurer on a secret corporate mission but transitions into a protector of the natural world. Her initial deceptive behavior gives way to cooperation, and her desire for a successful mission is replaced by a selfless decision to preserve a sacred place. During the film's credits, she is seen waving goodbye to Ash and his friends as they depart. Her character is later briefly seen in a montage in the subsequent film The Rise of Darkrai, and she makes a final appearance visiting the Forina region alongside the characters Butler and Diane from an earlier film. In terms of abilities, aside from her athletic and adventuring skills, her notable tools include her high-tech sunglasses and exploration robots. Her only known Pokémon are her two Weavile, which are capable of using moves such as Blizzard, Shadow Ball, and Ice Beam.