Is it more appropriate to move the verb form "one tense back" if the following text is given in isolation? I mean if you don't know that the text is a part of a summary.
(left, did not know, had picked up, found out, had, can, is wounded, managed, reached, was healed)
Frodo leaves the shire with three travelling companions: Sam, Merry and Pippin. First they do not know that the Dark Riders have picked up their trail already. But soon the four friends find out about that.
They have a few encounters with the Dark Riders which Frodo and his friends can only just escape. In one attack by the Dark Riders, however, Frodo is wounded badly. Still, his friends manage to escape with him. Travelling on, they reach the country of the elves. There Frodo is healed by Elrond, an half-elven.
There's no need- we can use the present there.