If you are ever in any doubt, which you shouldn't be, you should bet on the Player Characters. There will be some wacky plan, some last minute heroic success, an asspull Deus Ex Machina. You name it, it will happen to pull the players out of even crazy odds like taking on a giant who towers over the forest they're travelling through (see photo for clearer picture). Artistically, I enjoy this picture from with the hero in the silhouette view in the foreground of the massive loin cloth clad giant. It entirely sums up the heroic epic for me. That said, giants need better clothes. Imagine the killing a giant tailor would make clothing all those half naked or piecemeal clothed giants.
Let's hear those stories of surviving against impossible odds, or giant tailors.
Art from deviantart
LooneyDM *strikes a silhouette pose*