WARNING: The following contains spoilers for The Immortal Hulk: Flatline #1, by Declan Shalvey and Cory Petit, on sale now.
The Immortal Hulk: Flatline continues to show the despair Bruce Banner's living with, trying to figure out how to balance life with the Devil Hulk. It hasn't been easy due to the Green Door, the Leader and the One Below All manipulating him, which is why this story takes him back to Albuquerque to hide out in a diner washing dishes.
However, Banner can't hide forever, and he ends up getting smashed by Marvel's newest gamma-irradiated monster, his old teacher, Professor Noreen Noolan.
This issue starts with Banner going through the familiar motions and wanting to stay off-grid so that when the sun sets, he's far away from humans in case the Hulk gets mad. But Noreen tracks him down, making it clear she has one final lesson. She mentored him in the gamma program years ago and as Banner spots gamma all over her, she tells him that she studied the explosion that turned him and it changed her.
Banner, scared as dusk hits, tries to leave but after transforming and beating up bullies in a small town, Noreen decides class is in session and smacks him away. He travels hundreds of feet and lands in a warehouse where Noreen flies over to and continues to pummel him.
Rather than appearing like a creature, akin to A-Bomb, Abomination or the Leader, Noreen maintains her human form with a green aura around her. She throws him around like a veritable god, using telekinesis to drop tankers on Hulk and then carry him to the desert, embarrassing him in a way not even Red Hulk, Gamma Flight or the U-Foes could.
Even as Hulk tries to smack her with boulders, Noreen is impervious, leaving Hulk scared as he's never fought someone on her level. She hits him hard enough to knock him into the below place for a few moments. Noreen then melts his green shell away by controlling the gamma energy around him, but when he wakes up, he's on a hospital rooftop. Confused by the beatdown, Banner comes down and realizes she's contracted cancer and is dying there.
Her final lesson to him is to embrace his humanity and more so, mortality. That's the flatline that will allow him and Hulk to work together and become one. Neither Banner nor the Hulk understood this, evidenced by how many times each of them tried to kill themselves in the issue's flashbacks, but Noreen's there to show them there can be a synergy. And when Noolan dies in front him, her gamma 'soul' appears to float up, not down, so it gives Banner hope he can fix things with Hulk and that there's a way out of the Below Place that he feels resigned to.