Big Brother Premiere Reveals Mystery Houseguest, But They're Not 17th Player -- So Who Is?

There are even more mysteries than we expected, as some of the twists teased previously have come to light. We were introduced to the "Maniacal Mastermind," but we don't know who that is.

By the end of the night, we did learn who the "Mystery Houseguest" is and they did join the game ... but not as the 17th player.

So how does that work? What does that mean? It means that we really should expect the unexpected. The Houseguests learned right away that they need to be paying attention to every little thing happening in the house. Apparently, they need to pay attention to one another, too.

Just like A.I. interrupted the game constantly last season, this mysterious Mastermind character seems poised to interrupt this season over and over. But already, we like this sinister mask-wearing villain much better.

His first appearance came with the first big mystery of the night, leaving us excited about how this mystery theme will play out for the rest of the summer. It feels like so much more than a fresh coat of paint on the game, but something with truly transformative possibilities.

While host Julie Chen was talking, the lights cut out and when they came back on, both she and a "HOH relic" she'd just been talking about had vanished. It really is going to be a season built like a mystery because this one was all about paying attention to the details -- as in what Julie was wearing and the designs on the HOH relic.

The 16 HGs were split in half with eight of them participating in a challenge to save Julie, and eight of them trying to find the relic. All of this was happening before they'd had really any time at all to get to know one another.

What we learned through this competition is that Rylie, Mickey, and Morgan are trying to lay low during this early portion of the game, as all three of them were very open (in the Diary Room) about wanting to throw these first competitions.

To save Julie, they had to solve a bridge puzzle and then hear statements about her outfit, with only one of them accurate. In a wild choice, she was also literally behind that door. After Adrian copied Zach's work to finish the bridge first, Zach flew past him and saved the host.

In the other half of the competition, it was about finding the correct relic amid a sea of similar relics with slightly different patterns. Basically, this was about waiting until all the hints were revealed, because no one was paying that close attention before it disappeared. Will they be more keen to note details from here on in? In the end, Jimmy won this competition.

For their efforts, Zach got $10,000 for saving Julie, which isn't bad for one night of work. Jimmy got a much more complex prize -- he got to choose the only four people who will get to compete in the first Head of Household competition.

And guess what? Basically no one wants to compete in it. But in those conversations we started to learn a bit more about these competitors and their approaches to the game. Ultimately, Zae said he'd do it and promised not to target Jimmy if he won, Keanu said much the same, as did Vince -- but then in the DR he told us he might not honor that.

Ashley also said she'd be willing to compete, but told viewers that she would definitely throw it. That said, when she was in the competition, she reversed course and said she wanted to win, so clearly she's still trying to figure out her strategic approach here.

The competition was a pretty straightforward balancing act, with everyone struggling. Ultimately, Vince leaned on his juggling background and strategically figured out to use small movements to find proper balance on either side. It was enough to secure victory when no one else seemed close. So what will he do with this power?

Oh, and the power is worse than he thought, because Julie came on to reveal that last year's A.I. Arena has transformed into the BB Blockbuster and is now a permanent part of the game. That means each HOH has to nominate three players, and one of them can then save themselves in a competition before eviction.

If this runs all season, it means a hardcore competition threat could win their way to the end and even a Backdoor might not get them out. If the Houseguests figure this out, you can bet they'll be itching to eliminate anyone they see as a future threat sooner than later.

But before we could get into any of that, the Mastermind had a couple more tricks up his sleeve for this premiere -- and one that could have superfans rewinding this episode to sift through every scene again with a fine-toothed comb.

But before we get to that, here's where everyone stands with us after one night. Well... almost everyone.

Ashley Hollis (25, attorney) is a hardcore gameplayer in this house, but one who's doing a good job of laying low as she tries to figure out her best approach. She's got a slow burn to her but feels like someone to watch.

Vince Panaro (34, unemployed) is definitely bringing that Wild Card energy, while playing it very cool in conversations. What we've seen in DR entries is a player who's willing to do whatever it takes in a ruthless me-first/me-only way. It'll be interesting to see if he can keep that side of his gameplay hidden, because if he can, he could go very far.

Morgan Pope (33, gamer) is very strategic and very much taking in everything. She's also staying so low she's practically underground. We see it as more of a stealth strategy she's playing up very, very well right now, making her another we're definitely keeping an eye on.

Jimmy Heagerty (25, AI consultant) seems to have the house's sympathy for the tough spot he was put in, which is good as he's proving both likeable and getting in front of his willingness to play the game in a way that's coming across as non-threatening.

Zach Cornell (27, marketing manager) saved Julie, raising his threat level in competitions as he was leading the way on the bridge (until Adrian copied his work) and then strategically got ahead of Zach to win and save Julie. He's got a keen mind and is a quick thinker, which could serve him very well.

Mickey Lee (35, event curator) is already getting her flirt on, having successfully stolen Rylie's hat on the first night, as well as getting his heart and brain fluttering. She's been pretty open about her own ability to get distracted, but we've seen flirty women with men eating out of the palm of their hands do very well, so we're intrigued what she does with this aura she has about her.

Adrian Rocha (23, carpenter) is here to win this game. One of many superfans trying to hide their game knowledge, he's proving a strong competitor already, and someone who's a bit ruthless in his gameplay, as well as someone who's willing to stick their neck out. He needs to build relationships to balance that out.

Ava Pearl (24, aura painter), Katherine Woodman (23, fine dining server), Kelley Jorgensen (29, web designer), Lauren Domingue (22, bridal consultant), and Clifton "Will" Williams (50, college sports podcaster) are kind of just floating right now, not sticking their necks out. It's an effective strategy in the short term, but can burn you later.

Keanu Soto (33, dungeon master) made an early connection with Isaiah "Zae" Frederich (23, salesperson) basically over their overall bigness. But Keanu seems to think it could become a bromance with some strength to it. They are definitely going to have to work hard to not be seen as physical threats as this game progresses. A very public bromance could only make that threat look even bigger.

Amy Bingham (43, insurance agent) is loud and boisterous. That's about all she's done so far but it's already a lot. Think last season's Angela, but maybe (hopefully) a little less erratic.

Rylie Jeffries (27, professional bull rider) hasn't done much except for fall under Mickey's spell almost immediately. If he's this distractable by a pretty face, he might have a hard time with the rest of this game.

Perhaps the worst-kept secret of the whole night was the identity of the "Mystery Houseguest." Big Brother producers should have reached out to The Masked Singer to help craft more elusive clues than some of the incredibly obvious ones they came up with to tease the identity of the final Houseguest to enter the House.

At least the Houseguests themselves had no clue when the Mastermind interrupted Julie (again!) to tell them that another "Mystery Houseguest" would be joining them. With that, Big Brother icon, two-time player, and Season 13 winner Rachel Reilly entered the house.

But, and this is a big but, she was not the 17th Houseguest. She was the 16th.

How does that work if there were already 16 people playing this game? Easy ... one of the 16 Houseguests we met tonight is actually the "Secret Accomplice." They'd been helping the Mastermind manipulate the game all night long, like shutting off the lights, unlocking the door for Rachel to enter and the like.

If the Houseguests can identify who this person is, they'll get eliminated from the game immediately. But if they cannot, that person will stay and become the 17th HG. Will they ever be revealed, or will that trust remain frayed throughout the summer?

All will be revealed (but probably not really) when the season continues on Sunday at 8 p.m. Then, Big Brother settles into its usual Wednesday, Thursday, Sunday schedule.

This year is also adding an every-other-Friday show, starting July 25, to be hosted by BB veterans that will offer exclusive footage, interviews, and other surprises. Will it be worth watching? It's a (Hotel) Mystère!