Tohru and Kobayashi-san is the first chapter of Kobayashi-san Chi no Maid Dragon.
The chapter starts with Kobayashi going to the rooftop of her workplace, where the dragon Tohru is waiting for her. Kobayashi hops on her, scolding Tohru for being in that form in plain sight, and the two fly back to Kobayashi's home. Shortly after landing, Kobayashi complains that Tohru's back is too hard for her back pain, and that she will no longer use Tohru to head to work. However, Tohru complains and begs Kobayashi to reconsider, prompting her to relent a little, saying that she'll use her once in a while.
Inside, Tohru has prepared her grilled tail for dinner, much to Kobayashi's distaste. Tohru eats the tail herself, pointing out the trouble she went to making it. Kobayashi, out of curiosity, asks what Tohru likes, to which Tohru replies that she loves Kobayashi, and that she'd do anything for her to repay her debt. Kobayashi requests that she stay at the house, in order to keep from standing out. However, the next day, when Kobayashi leaves for work, Tohru is unsure of what to do. She phones another dragon, Fafnir, for advice, and he tells Tohru to kill anyone who attempts to steal Kobayashi's treasure.
Coincidentally, shortly after hanging up on Fafnir, two criminals are sneaking around outside Kobayashi's apartment, believing the apartment to be empty of any inhabitants at the time. They pick the lock and open the door, only to be greeted with Tohru in her dragon form. Terrified, the two thieves run off. Later, on her way home from work, Kobayashi encounters the two would-be criminals turning themselves in to the police, asking for help dealing with the monster. As Kobayashi returns home, Tohru offhandedly mentions that she didn't have an opportunity to kill the two robbers.