After the events of The Night to Remember, Thomas and all of his friends from The Island of Sodor were given a gift from Princess Celestia, Princess Luna and Princess Cadance, The ability to transform into Earth Ponies, Pegasi, Unicorns and Alicorns at will. Then, Lady was married to Thomas and became a princess and they had a new born son named "Edmond".
One beautiful day
It was a beautiful day in Equestria, the engines were all gathered by Princess Celestia, Princess Luna and Princess Cadance as they bestow a gift. They gave the Engines of Sodor the ability to transform into Earth Ponies, Pegasi, Unicorns and Alicorn at anytime.
Later that night, Thomas and Lady had a little talk about how much they're enjoying being ponies. Then, Thomas proposes Lady and she said yes. The Next Day, They asked Princess Twilight Sparkle, Princess Sunset Shimmer and Trixie to help prepare for their wedding and they agreed.
Thomas and Lady's wedding
Later, Thomas and Lady got married with Friar Tuck preforming the marriage, Percy as Thomas' Best Stallion, Emily as Lady's Mare of Honor, Duck, Donald and Douglas, Oliver, Toad and Stanley as the Groomsstallions, Annie and Clarabel, Rosie, Mavis, Flora and Daisy as the Bridesmares, Luke as the Ring Bearer and Pearl Krabs as the Flower Girl. Then, Princess Celestia, Princess Luna, Princess Cadance, Princess Twilight Sparkle and Princess Sunset Shimmer proclaimed Thomas and Lady the new Prince and Princess of Sodor and Equestria.
A New Prince
Later, Months past after Thomas and Lady's honeymoon and they were blessed with a newborn son, A prince who was given the name, "Edmond".
Yuna's New Friend
At the daycare center, Edmond was brought here to be played with as he plays with Yuna and that was before the friendship of Prince Edmond and Princess Yuna.