Today is Wilfred's birthday. The mice arrange a surprise picnic at Bluebell Bank and Primrose makes sure that Wilfred doesn't know about it yet. Basil accidentally misplaces Wilfred's picnic hamper. Wilfred recovers the wrong hamper but his father gets the right one and Wilfred's birthday celebration begins.

Poppy and Dusty have seen other so often, Dusty wishes to propose to Poppy. Wilfred and Primrose try to bring the couple together. Finally comes the day of the wedding. Unfortunately Wilfred's blunder causes the wedding raft to drift away from the bride, but Wilfred manages to catch it and the wedding commences.

During the harvest season, Lord Woodmouse and Primrose go picking blackberries, while Wilfred looks for adventure by trying to find a creature called The Weasel. Primrose and Wilfred get lost as they explore the wilderness, so all the other mice send out a search party. The search party finds Primrose and Wilfred, so they all return home.

Wilfred is looking forward to the deep snow to ride on his tobaggan. Better still when the snow covers the third notch comes the Snow Ball celebration at the Oak Palace. Soon Basil, Wilfred and Primrose get trapped in one the snow tunnels. Primrose finds a way out and summons the other mice to help. After that everyone celebrates.

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.