In the old castle Abo (Finland) there lived an old brownie. He was only friends with the brownie from the cathedral and the old castle gatekeeper Matts Mursten, whom he met when he, as a boy, climbed into the basement for cartridges, fell into the rubble and was released by the brownies. Matsu brownie helped look after the castle, but remained invisible. The gatekeeper could see him only when he became a very old man: he took him home to his Hollow Tower and showed untold treasures, the cat Murra and the wolves, in which hunters for his good turned. The owner of the tower told Matts that the old Väinämäinen was sitting under the castle and was waiting for his beard to grow back and the confinement would come to an end, while he was singing.

The gatekeeper invited his ancient comrade to the wedding of the great-granddaughter of Rosa. The brownie was invisibly present at the celebration and even put an old gold crown on his bride’s head - his present. Despite the promise to the house, Matts talked about where the crown came from, and the cousin of the groom and the grumpy mother climbed into the tower for treasures, and remained there.

The castle gradually fell into disrepair, and one day while walking along it, Matts, Rosa and her baby Eric met a brownie. He wanted Eric to keep the castle in order, and the refusal made him furious - but the old man’s song sounded ... Matts died while the song was being sung. Rose undertook to protect the castle, Eric took care of her, and the brownie invisibly helped them.