Does a saga's ability resolve in time to save the saga?
You will get to return the Saga to your hand.


  714.4. If the number of lore counters on a Saga permanent is greater than or equal to its final chapter number, and it isn’t the source of a chapter ability that has triggered but not yet left the stack, that Saga’s controller sacrifices it. This state-based action doesn’t use the stack.


The bold part makes it so that as long as the "return to your hand" ability is on the stack; the state-based action that would make you sacrifice it doesn't do anything yet.