Frankenstein Summary & ending explained

My dear Margaret,

You told me not to come this far north. Every mile closer to the pole makes my heart beat faster. Somewhere past this ice is a sea no one has ever sailed, and I mean to be the first.

Only one thing is missing on this ship: a friend. My sailors are brave, but none of them shares my dream.

Last week the ice closed around us completely. At about two in the afternoon the fog lifted, and we all saw it: a sledge pulled by dogs, racing north across the frozen plain half a mile away. The driver was shaped like a man, but far too large to be one. We watched him through our telescopes until he vanished among the ridges of ice. We were hundreds of miles from any land.

That night the ice broke up. In the morning my men were leaning over the rail, shouting at someone below. A second sledge had drifted to us on a slab of ice. Every dog but one was dead. Inside lay a man so frozen and starved I thought he was a corpse.

My men begged him to climb aboard. He would not move until he had asked me one question.

"Where is your ship going?"

North, I told him, to the pole. Only then did he let us lift him onto the deck.

He has been with us for days now, gentle, educated and so full of grief that it frightens me. When I told him that I would give my life, gladly, to reach the pole, he covered his face and wept.

"You poor man," he said. "So you have caught it too, the fever that ruined me? Then hear what happened to me. It may save you."

He begins tonight, and I will write down every word. But I keep thinking of the giant on that first sledge, racing north ahead of him.