This is "A Boy and a Girl with a Cat and an Eel" painted in the Dutch tradition by Judith Leyster around 1635. The painting seems to be playing with a well-known saying - 'he who plays with cats gets scratched'. You could interpret it as both delightful entertainment and a warning. Here, we see an older brother leading his little sister astray. She's got that wicked twinkle in her eye and is ready to give the cat a tug. The boy on the other hand has tempted the cat with an eel but keeps it out of reach, making the cat quite uncomfortable.
Leyster used dark colours for their costumes and background to highlight the fresh complexions, sparkling eyes, and lively expressions of the children. They're dressed like mini-adults as was the custom in Holland at the time. Their neat hair and clean clothes suggest they come from a prosperous, middle-class family, which is unusual for this type of painting.
A Boy and a Girl with a Cat and an Eel hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.