Rosetta jumps onto the narwhal and gently carries Pfaff back to the boat. Only then did she realize that part of Pfaff's body is beginning to rot.
How'd this happen! But you didn't get hurt, Grandpa...
The Punishing... Damnit... And at a time like this...
Rosetta has heard of the Punishing Virus from Pfaff not long after setting out to sea. It is a terrible virus that had ravaged the world at the height of the Golden Age.
The horrific virus had spread everywhere except high altitude areas like the Arctic. Only a special serum can mitigate the effects of the virus.
So, Grandpa, the thing you said I had to inject everyday... That's the serum?!
Rosetta searches Pfaff for a shot of the serum in a panic, but Pfaff gently grabs her hand and shakes his head.
Don't bother looking... I've run out of mine... for quite some time now...
Rosetta checks the boat. There is only enough serum left for one person to make the voyage back.
Why...? Why didn't we go back when you knew it's not going to be enough?!
I have to kill the narwhal, no matter what—even if it kills me.
But why?! I don't understand...
Because Grandpa has sinned. Far more than the Forest Guards... So there's no need to feel any regret.
But Grandpa, you've never done anything bad. How could you be a sinner? They must've made a mistake!
Rosetta, listen to me. Killing the narwhal is our only chance to be allowed into the ARU.
If that's the case, then I don't wanna join 'em! Weren't we doing okay just living in the forest?
For me, it is, but not for you. I can't allow you to be stuck there your whole life. You need friends... You need a future...
Rosetta becomes quiet. She has friends in the port. If she could live a life like an ordinary girl...
Pfaff shoves the high-voltage harpoon into Rosetta's hand. He points it at the narwhal's eye and nods.
Kill the narwhal while you have the chance. Take the core of its electronic brain back to the port manager. He'll know what it is.
Rosetta takes the harpoon. She shambles absently toward the narwhal, staring into its eyes.
The narwhal is tranquil as if it has accepted its fate. They both stare silently into each other's eyes.
(Once you kill it, Rosetta, you'll be free...)
(You'll no longer have to bear this sin that never was yours. You'll finally get to be a normal girl. You'll get to live without any regrets.)
But Rosetta shakes her head instead. She throws the harpoon into the sea and kneels beside the narwhal.
If you are the Guardian Spirit of humanity, please listen to my only prayer...
The young maiden can no longer hold back her tears.
Please, save my grandpa... Please... I beg of you...
Only with the speed of the narwhal, can the two of them make it back to New Murmansk with the serum they have left.
Rosetta, give up... It's not a guardian spirit at all. It won't respond to you.
We created it... It's just a cold and heartless machine. It's an irrevocable proof of our sin in a foolish age.
But it chose to protect humanity rather than fight. It's our friend, not a cold-hearted weapon.
The eyes of the narwhal flicker. It lets out a bellowing roar. Toiling visibly, it makes a hard turn and begins dragging their boat to the north.
Impossible... The narwhal's M.I.N.D. awakened...? Because of Rosetta?
We can't keep calling it the "Guardian Spirit" or just a "narwhal". It should have its own name.
To become friends, we must know each other's names. Right, Derek?
The narwhal lets out a series of groans as if dissatisfied with the silly name, taken and arranged from Drake Passage.
Grandpa, no matter what happened in your past, the three of us have to get back alive. It shouldn't end here!
(Rosetta, you've really grown up... Turns out I was the only one trapped in the sins of the past...)
And with that, the journey between the two of them and Derek, the narwhal, begins anew.
But this time, not to a perilous end, but toward their last hope.