This page was fun to colour.

Any plan to terraform Mars depends on what technologies have been invented by the time it happens. For the purposes of this story, I’m assuming we had the ability to do the following when people first moved to Mars:

1.) Give it a breathable atmosphere, ie, add heaps of oxygen and nitrogen to the air. I haven’t done the math to determine if there’s enough oxygen locked in atmospheric CO2, rocks, ice, or underground sources to make a viable atmosphere. I’m guessing those numbers don’t exist with any accuracy. I’m also guessing there isn’t, in fact, enough. Which means it would need to be brought in from away, most likely from the Oort Cloud (most of what’s in the Oort amounts to dirty snow, and despite being far away, those bodies are small so there’s less gravity to overcome when transporting chunks of Oort ice). You would need enough atmosphere to raise the air pressure considerably to have the character in panel 2 do what he’s doing.

2.) Give it enough water to make lakes, rivers, seas, and fluffy clouds. Again, I don’t think it’s known how much water is actually available on Mars, but we’re already bringing in chunks of ice and very carefully crash-landing them on the surface, so, that’ll sort itself out. All the plants and soil you’ll want to transport to Mars will depend on a healthy water cycle.

3.) Raise the temperature using greenhouse gasses. I’ve depicted Mars as being cold in the summer and frigid in the winter, but it’s still a lot warmer in this story than it is in the present.

What you can’t do, at least not without technology that doesn’t exist in this world, is solve the problem of Mars being constantly bathed in cosmic radiation, having less than half of Earth’s gravity, or the fragile grasp the planet will have on the atmosphere you give it. More on that later.

↓ Transcript
Panel 1: A domed city sits on the harsh, rocky surface of Mars as it was in the early days. Maida's voice-over: "Mars was terraformed ages ago, when my ancestors first moved there."
Panel 2: Early Martian settlers in bulky suits cautiously test taking off their breathing apparatus. Big cooling towers marked "O2" slowly change the air in the background. Voice-over: "But terraforming can only do so much. The first Martians changed themselves as much as they changed the planet."
Panel 3: Maida lays on a hospital bed as a medic puts a mask on her face. Voice-over: "In order to survive on Earth, we have to be changed again."