Episode 4 of "Reborn as a Vending Machine, I Now Wander the Dungeon" begins with the protagonist Boxxo being transported by hired workers to reinforce the walls of a village. Among the workers is a familiar face from a previous episode who had once stolen from Boxxo, making Boxxo suspicious. It turns out that the workers actually intended to steal Boxxo.

When the workers demand supplies from Boxxo, they accidentally damage the vending machine. Instead of using his points to repair the damage, Boxxo decides to increase his durability by 10 points, which costs him 1000 points. This decision successfully prevents further damage from the workers' actions.

The workers then take Boxxo to a mansion owned by a girl named Hulemy, who is fascinated by the vending machine and wants to study it. She had previously been mentioned by Lammis as someone she would like to meet. Hulemy discovers that Boxxo's phrases "Hello" and "Too bad" serve as confirmation and denial, respectively. In this way, Hulemy engages Boxxo in a series of yes/no questions.

Over the course of the evening, Boxxo demonstrates more of his abilities, such as transforming into a different vending machine and erecting a protective barrier around himself. When the workers return, Boxxo quickly dispenses adult magazines to distract them and buy time.

As dawn breaks, Boxxo helps Hulemy by providing her with hair care products and clothing. Suddenly, the mansion is raided by the Hunter Association led by Lammis, who is searching for Boxxo. However, Boxxo and Hulemy discover blastite, a hidden explosive, in the warehouse. When the blastite detonates, Boxxo uses his protective barrier to shield them.

As the barrier's energy wanes, Boxxo uncovers a stash of gold coins stolen by the workers, and Hulemy quickly feeds the coins to Boxxo to maintain the barrier. When Hulemy begins suffocating due to lack of oxygen, Boxxo transforms into an oxygen dispenser and saves her. The episode ends with Boxxo and Hulemy escaping, leading to a joyful reunion with Lammis.