12 year old Jackie is a familiar face at Amsterdam's famous Rijksmuseum, where her mother is a curator spending long hours looking after an important new exhibition of Rembrandt artworks. Left to fend for herself and her younger sister Piek, Jackie is a capable housekeeper, making sure everyone is in the right place at the right time. But her ordered life is suddenly turned upside down when one of Rembrandt's most famous portraits comes to life right in front of her.
Oopjen steps out of the painting to beg Jackie's help. Jackie now has an even bigger challenge, hiding her new friend Oopjen from everyone whilst helping to track down her sister Aeltje, who is herself the subject of a long lost portrait - and the spitting image of Jackie. For Oopjen, a woman from the Golden Age, the 21st century is a big adventure.
Will they find Aeltje in time before the world realises Oopjen's portrait is an empty frame? A lively, humorous and heartwarming adventure about friendship and loyalty.