The Enchanted World of Brambly Hedge S01 E05 The Secret Staircase

Midwinter celebration is coming. Primrose and Wilfred are assigned to recite the Midwinter Poem, and they discover a secret staircase concealed in the attic and many old rooms within. They find stumble down a secret tunnel making it in time for the Midwinter celebration, but they keep the old rooms a secret.