Avalor has spent years in peace and prosperity, but everything comes to the verge of ruin when the Shadow Realm is opened, letting in a rogue Spirit Guide and his army of wraith-like Shadow Spirits. Tragedy shakes the land and the Kingdom's leaders will be tested like never before. (Elena x Mateo, Gabe x Isabel)

When a magical watch launches Elena ten years into the future, she discovers that Avalor has been turned into a land full of desolation and despair - and is ruled by none other than the Delgados. With the help of her now much older friends and family, Elena must find a way to return to the past and fix the timeline to prevent the Delgados from sabotaging Avalor ever again.

Months after the defeat of the Malvaran sorcerers, talk turns to the royal wedding. Mateo wonders if he is worthy of Elena and finds a clue revealing that countless prisoners from Shuriki's reign may yet live on an island in the North. Mateo and Elena set off on a voyage to solve the mystery and bring their people home. A journey promising adventure, romance, and self-discovery!

So basically Santana got pregnant after Smooth Criminal. Set during season three. Rated T for now, but I might have to change it to M at some point.