There is gonna be one, but nothing is set yet. they might even backfire the whole thing! If あなた want a Spirit 2, type in `Spirit 2 petition' & click on the first link.
anyway, it should be about their life with their foal... But something bad happens. Like the humans rebuilding the railroad または something.
I think Rain's and Spirit's 子馬, 仔馬 will get captured and Little Creek dies, So it is up to the rest of the herd to save their 子馬, 仔馬 without getting killed または hurt によって all the weapons the bad guys have.