The unveiling of the NCAA tournament bracket represents an annual reinvestment in college basketball for those who only pay casual attention — or none whatsoever — from November to mid-March.

That’s OK. If you’re dropping back in from Mars, the adjustment is quite easy this season. Just remember one word.

Zion.

Don’t worry. You’ll hear that name a lot the next few weeks. March Madness probably will become March Zionness.

Zion Williamson’s return from a knee injury caused by a defective Nike shoe has given Duke its mojo again and powered the Blue Devils to the No. 1 overall seed in the tournament.

Duke’s conference mates felt plenty of love from the selection committee, too.

In a move that was historic but not unexpected, the top three No. 1 seeds went to ACC teams — Duke (East), Virginia (South) and North Carolina (Midwest). Gonzaga received the top seed in the West Region.

This is only the second time in tournament history that one conference earned three No. 1 seeds, joining the Big East in 2009.

“They earned their right to be there,” said Bernard Muir, chairman of the selection committee.

Three teams from one conference earning top seeds is bound to invite second-guessing. But what happened below them was truly baffling.

Michigan State won the Big Ten regular-season title and the conference tournament championship and was under strong consideration for a No. 1 seed entering the weekend.

Instead, the Spartans received the No. 2 seed in the East Region. They were deemed the second No. 2 seed by the committee — behind Tennessee — but were placed in the same region as the tournament’s No. 1 overall team, Duke.

That makes no sense. MSU coach Tom Izzo wasn’t happy either, telling reporters that his team didn’t get what it deserved.

It’s arguable that Michigan received a more favorable path as the No. 2 seed in the West, despite going 0-3 against Michigan State this season, including a loss in Sunday’s title game.

Weird.

The Big Ten led all conferences with eight total bids, but the ACC, with seven entrants, was the clear winner.

“For all these teams, these three teams especially to do so well, it’s remarkable,” Duke coach Mike Krzyzewski said this weekend. “It’s unusual for this level.”

Duke was an easy choice for No. 1 overall once Williamson returned from injury and picked up where he left off. He missed the final six games of the regular season after his shoe exploded against North Carolina, causing a knee injury. The Blue Devils went 26-2 with him, 3-3 without him.

A faulty shoe is his only kryptonite. College basketball hasn’t seen a supernova talent like Zion enter its orbit in a long, long time.

He is 6-7 and 285 pounds with a freakish combination of strength, athleticism and agility. He explodes for dunks as if he was double-bounced from a trampoline.

There was breathless debate about whether Williamson would return this season, or should return and potentially risk further injury that might cause him to lose millions in future earnings. Sounds like he never gave it any thought.

“Those six games I sat out, when you see your brothers going to war battling and there’s nothing you can do but sit on the sideline and cheer,” he said. “There’s nothing wrong with that, but I’m not that type of person. I want to be out there with them, and I made a commitment to them, and I would be a bad person if I went back on my commitment.”

Duke has three NBA lottery picks in Williamson, RJ Barrett and Cam Reddish and a terrific point guard in Tre Jones, the pride of Apple Valley and brother of Tyus. The younger Jones doesn’t live in his brother’s shadow as much as he’s following a similar career arc.

The freshman who commands the most attention is undeniable. And if there were any doubt about Zion’s health, he answered them emphatically by averaging 27 points and 10 rebounds in three ACC tournament games. He made 33 of his 43 shots.

Yep, he’s fine.