The Federation starship Enterprise, under the command of Captain Jean-Luc Picard, is assigned to transport the beautiful Salia, future ruler of Daled IV and her governess Anya, from a planet to which she has voluntarily exiled herself.
He introduces her to Thalian chocolate mousse, and takes her to the holodeck to show her several other worlds after she expresses an interest in exploring the galaxy.
Anya, touring the ship, first gives advice on warp engines and then discovers a crew member with a virulent disease being in a containment field in sick bay.
The Chief Medical Officer, Dr. Pulaski, refuses and insists the disease is contained but Anya transforms into a large monstrous form, easily matching Worf's strength when he tries to intervene.
When Captain Picard arrives, Anya reverts to her petite humanoid form and defiantly explains her actions.
[1] In February 2019, Den of Geek noted "The Dauphin" as including awkward romantic elements, with Wesley ignoring (normally obvious) concerns because of his crush-like emotions towards the visiting alien.