During a Wonderbolts exhibition at Mt. Aris, Rainbow Dash accidentally crashes at Sonic Rainboom speeds, nearly killing her. Her recovery is slow and painful, grounding her for months. While land-locked, she learns to appreciate life from the new perspective, as well as the pony caring for her.
At the same time, Applejack watches others form families of their own and starts to wonder if she’ll ever get a special-somepony for herself, or if she’ll end up alone. But she doesn't get any time to ponder that before she's suddenly thrust into a caretaker role for a badly wounded Pegasus...
(Found the cover on EQD, not sure who made it...)