Is It Wrong to Try to Pick Up Girls in a Dungeon?: Arrow of the Orion is a 2019 Japanese animated fantasy film based on the light novel series Is It Wrong to Try to Pick Up Girls in a Dungeon? written by Fujino Ōmori and illustrated by Suzuhito Yasuda. The film was released on February 15, 2019 in Japan, and received limited theatrical releases in other regions later in the year. The film takes place between seasons one and two of the anime series.
Plot
Bell Cranel takes part in a usual day in Orario, exploring the Dungeon alongside Liliruca Arde and Welf Crozzo, before attending the Holy Moon Festival alongside his goddess, Hestia. They notice Hermes putting on a challenge to pull a spear out of a crystal, stating whoever does will be blessed by the goddess of purity and get to take a trip outside the city. Hestia convinces Bell to do it, and when he touches the spear, he hears a voice confirming he's the one, causing the crystal to shatter. Hermes congratulates Bell and introduces the event's sponsor, Artemis, an old friend of Hestia who's happy to see her again, but shocked when she sees her embracing Bell, calling him her "Orion".
Hermes informs Hestia's group that Artemis sponsored the event in order to seek help to defeat a monster outside of Orario that her Familia had trouble dealing with. Bell questions why he should be the one since there are stronger adventurers, but Artemis insists since the spear chose him, because of his pure soul. Hestia agrees to accept the quest, with Lili and Welf also agreeing to join in.
After a week flying on dragons to their destination, the group rescues a mother and her child from some monsters. Bell easily defeats them using the spear, but Hermes warns him not to use it again. Camping for the night, the group discuss the outbreak of monsters they learned about from the mother, with Hermes wondering if it has to do with their mission. He explains that at the Elsus Ruin, there was a monster called "Antares" that was sealed off long ago, but has since started to regain power, so he and Artemis teamed up in order to defeat it, also informing them that the spear they possess is imperative to killing Antares. Before going to sleep, Hestia and Artemis talk about how they feel about Bell, with Artemis also vaguely referring to what happened with her Familia, and Hestia noting how much she's changed.
The next day, the group nearly reach their destination, but are knocked out of the sky by a barrage of light spears, causing them to crash land in a dead forest close by. They are surrounded by a group of monsters, but are saved by Ryuu Lyon, who is assisting the rest of Hermes Familia, who have been waiting for Hermes' return. Asfi explains the situation, how the monsters have been ravaging the land, and that they've been unable to reach the gate that blocks their path to Antares.
That night, Hermes and the boys attempt to spy on the ladies while they bathe, but are quickly foiled, while in the ruckus, Bell manages to escape and stumbles upon Artemis bathing alone. The two talk about her relationship with Hestia, and what kind of a hero Bell wants to become, before Artemis asks Bell for a dance. He accepts, and she talks to Bell about the 10,000 years of romance the gods were promised when they descended to Earth.
The following morning, the group plan their battle strategies, with Hermes Familia acting as decoys, while Artemis, Hermes, Bell, and the rest charge into the ruins. They're able to pass through the gate thanks to Artemis, but are left struggling with the monsters that they learn are capable of self-regeneration and evolution. Meanwhile, back in Orario, the monsters in the Dungeon have started to go berserk, leading the Guild to issue an emergency request for first-class adventurers to deal with it.
Artemis' group finally reach the location of Antares, to surprisingly find the great monster containing the crystallized body of Artemis within its chest. Hermes then reveals that the Artemis that they ventured with was merely a fragment of the original, and now with Artemis' body within it, Antares has gained the ability to utilize her divine power. As a result, Antares fires a beam of light into a crescent moon shaped scar in the sky, creating what appears to be a 2nd moon, something the Gods in Orario recognize as an Arcanum spell: "Artemis' Arrow." The Loki Familia, and eventually even Freya Familia, take charge in holding back the rampaging monsters from escaping the Dungeon.