It's civil war inside the Big Brother 18 house! Without a villain like Victor or Jozea to unite against, the super-sized alliance the 8 Pack has already imploded. Not only is alliance member Tiffany on the block and possibly going home, but there are two other plots within the group to potentially target either Da'Vonne or Frank next week.

So who won the fourth week in the Big Brother house? Check out our power rankings below. (For previous rankings: Week 1, Week 2, Week 3.)

Team Unicorn (team average: 6)

Natalie: Showmances can be the death of a player in the BB house, but Natalie is using her flirt-mance with James very wisely. When he told her that Frank won Road Kill, Nat didn't tell a single soul what she learned, including her fellow Spy Girls, Bronte and Bridgette. Sure, she tried to drop some hints here or there, but Natalie proved her trustworthiness to the other side of the house and won the week.
Grade: 7.8 (Season average: 5.9)

James: After getting friend-zoned by Meg all last season, James is finally getting a little TLC in the BB house courtesy of Natalie. But beyond giving him someone to flirt with, Natalie is proving to be a reliable ally who's good at keeping secrets and always sticks to her word (remember her insistence on voting to keep Jozea in Week 1?). James has also said that he would be willing to evict Natalie if needed, so it's good to know he's still keeping his eye on that $500,000.
Grade: 6.8 (Season average: 6.4)

Bronte: Who are you fooling, Bronte? Her attempt to seduce James into telling her who won Road Kill while taking off her shirt was pathetic. And while Bridgette might buy Frank's excuse that he only put Bronte on the block because he knew she'd be safe, Bronte has few allies in the house and if Tiffany successfully pulls off a Hail Mary pass, Bronte could easily be sent packing.
Grade: 3.5 (Season average: 3.1)

Big Sister (team average: 6.7)

Paul: Paul is once again on the block, but resting easy. Is he this season's Johnny Mac? Paul is officially on his own this week with Victor and Jozea gone, but that doesn't mean he's without friends in the house. Paul's been cozying up with Paulie and Bronte, giving him good ties to both sides of the house without having to declare loyalty to anyone in particular. Paul will have to make a move eventually if he wants to stay safe, but for right now, he's exactly where he should be.
Grade: 7.6 (Season average: 5.4)

Da'Vonne: Instead of blowing up at Frank's misogynistic behavior, Mama Day kept her kept her cool, publicly accepted his apology while privately plotting against him. And even though she's the one who put a target on Tiffany in the first place, she's been doing work to try and keep Tiff safe so that they could make a move against Frank together next week.
Grade: 7.2 (Season average: 7.1)

Zakiyah: Zakiyah is in a fine position, but she needs to do something to distinguish herself from the pack. One month in, and it's still unclear what Z's game strategy is or if she could be any sort of comp threat.
Grade: 5.4 (Season average: 5.5)

Freakazoids (team average: 5.2)

Nicole: Nicole just seems confused this week. Does she want to target Frank next? Does she want to target Day? Does she actually want Tiffany out? We have no idea, and we don't think Nicole does either.
Grade: 6.2 (Season average: 6.9)

Tiffany: Tiffany is in a bad spot this week, but it's not really her fault. Her own alliance members can't see past her being Vanessa's sister, and they're constantly accusing Tiffany of being emotionally manipulative, sneaky and paranoid. But is it paranoia when your own alliance really is plotting to evict you?
Grade: 4.8 (Season average: 5.6)

Corey: Corey is just there. And if it weren't for his relationships with Paulie and Nicole, we'd probably forget about him completely. Step it up, dude!
Grade: 4.5 (Season average: 5.6)

Category 4 (team average: 5)

Frank: Frank's game continues to be on shaky ground. His disrespectful attitude towards the women in the house, Day in particular, upset many of the houseguests, which put an even bigger target on his back. However, with Bridgette as mouthpiece, Frank still managed to run the house this week and even launched a plot of his own to take out Day.
Grade: 6.6 (Season average: 7.4)

Paulie: It's astounding how little heat there is on Paulie. While everyone is afraid of Tiffany making it to the end like Vanessa, no one seems to notice that Paulie's playing a very similar game to his brother Cody, who made it to the Final 2. If Paulie can keep up the charm and back it up with strong comps and big moves, he could be a real contender this season.
Grade: 6.4 (Season average: 7.3)

Michelle: It's shocking that Michelle has never been on the block. She doesn't play a great social game, isn't great at comps and shows no talent for strategy. For a superfan, she doesn't really seem to understand how to succesfully play the game.
Grade: 4 (Season average: 4.8)

Bridgette: Despite winning HOH and POV, Bridgette is this week's loser by a mile. Everyone in the house knows Bridgette's HOH is really Frank's, and she seems perfectly content being wrapped around his finger. Even when Frank admitted he was the one who put her on the block in Week 1, Bridgette responded by saying, "Thank you." If Bridgette wants any real shot of winning this game, she needs to stand on her own and realize when someone's using her.
Grade: 3 (Season average: 3.5)

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