In a nutshell
The Sentinels return.
Editor: Stan Lee
Writer: Roy Thomas
Penciller: Neal Adams
Inker: Tom Palmer
Letterer: Sam Rosen
In Manhattan, Lorna Dane is abducted from her apartment by Sentinels. In Egypt, Iceman arrives with the authorities, who recognize the Pharaoh as noted archaeologist Professor Abdol. The Pharaoh claims Alex is a dangerous criminal while Cyclops tries to tell them the truth. When the authorities decide to arrest the X-Men, Alex, worried that he'll hurt someone with his overcharged powers, runs off into the desert, followed by the X-Men, who quickly dispatch the Egyptian police. Hiding inside a cave, Alex is captured by a Sentinel. Thinking of using Cerebro to try and find him, Cyclops attempts to contact Lorna to set it up for remote access, but finds only her empty, destroyed apartment. Worried about what happened to her, Iceman and Beast head back to America to investigate, leaving Cyclops, Angel and Marvel Girl to continue the search for Alex.
Back in New York, Iceman and Beast investigate Lorna's apartment, but are interrupted by the police, who attack the two mutants. Escaping, Iceman and Beast go to Cyclops' New York apartment and see a news report featuring Judge Chalmers announcing his study which proves mutants are a menace. Chalmers introduces Larry Trask, son of the Sentinel's creator Boliver Trask, who declares that the Sentinels live!
2nd Story: "The Female of the Species!"
The extent and uses of Marvel Girl's powers are discussed.
Firsts and Other Notables
The Sentinels return, and this issue is technically the first appearance of the Mark 2 Sentinels.
Larry Trask, son of Sentinel creator Boliver Trask and the mastermind behind the Mark 2 Sentinels, also appears for the first time. He believes the X-Men are responsible for the death of his father, giving his general anti-mutant campaign a very personal motivation.
His ally in this is federal judge Robert Chalmers, also appearing for the first time, who will be revealed to be an old friend of the Trask family. Chalmers heads up the Federal Council on Mutant Activities, which makes it the first anti-mutant government organization to appear in the book.
This is the last issue to feature a regular backup, and the backup is written by former Marvel staffer Linda Fite, the only woman to write an X-Men story in the title's history. Marvel Girl doesn't get a full origin story, presumably because we saw her joining the team in issue #1, though Bizarre Adventures #27 will fill in some details of her pre-X-Men life.
One of the pages that is often used to illustrate the innovations and dynamism Neal Adams is bringing to the book occurs in this issue, the famous "Beast falling out the window" page:
A Work in Progress
The Pharaoh is given a real name (Professor Abdol) and a job as a noteworthy Egyptian archaeologist. Somehow, he managed to change out of his super-villain garb between issues, which helps sell his "I"m innocent and the X-Men are bad" story to the cops.
Ah, the Silver Age
The Egyptian police ride camels, and Cyclops refers to them as "camel jockeys".
The Marvel Girl feature goes about as well as you could expect, given the times.
It's established that Lorna and Iceman are still a couple, and Iceman freaks out when the X-Men discover her missing from her trashed apartment.
The police attack Beast and Iceman because they're mutants, and of course, the reintroduction of the Sentinels is veiled in anti-mutant rhetoric.
The Awesome and Terrible Power of Cyclops
After Alex runs off into the desert, an angry Cyclops unleashes his optic blast on the Egyptian authorities.
The Awesome and Terrible Power of
Oh, the angst! The face-palming angst!
Little brother, bigger angst.
Roy Thomas on ending the backup stories
"Neal wanted to expand the lead story in each issue from fifteen to a full twenty-two pages. He wanted to drop the backup...I agreed to do it - in fact, I liked the idea - but we would probably have been in better shape if we had kept the lead to just three-quarters of the book. But there was just this irresistible temptation to get the entire book drawn by Neal."
DeFalco, Tom. Comic Creators on X-Men. London: Titan Books, 2006. p28
The Thomas/Adams run kicks into high gear with this issue, beginning their first riff on Lee/Kirby material by bringing back the Sentinels. And with the Sentinels comes a return of the one of the books core themes: prejudice. Aside from a few random asides from bystanders and cops, it's hard to believe X-Men has more or less ignored the concept of anti-mutant prejudice since the last go-round with the Sentinels back in issues #14-16. As a result, this story almost serves as a reintroduction to the idea of mutants as a persecuted minority feared and hated by the general public, and this time the idea doesn't fade into the background when the story ends, instead remaining a defining characteristic of the title to this day.