Kourtney Kardashian was absolutely furious this weekend.
On Saturday, the eldest sibling in the KarJenner family hosted a Fast and the Furious-themed party for her sons Mason, 7, and Reign Disick, 2, (who both celebrated thier birthdays on Wednesday, Dec. 14) at her home in Los Angeles.
Her daughter Penelope Disick and pals like hair stylist Jen Atkin and makeup artist Hrush Achemyan were in attendance for the festivities. And one notable guest was her sister Kim Kardashian West, who brought her children North and Saint to her nephews’ birthday party.
“Kim spent several hours at the birthday party with her kids,” a source tells PEOPLE. “She looked very pretty and also seemed happy. Kanye [West] was not with them.” The source added that Kardashian West was wearing a plain gold band on her ring finger.
Kardashian West’s appearance at the party comes in the wake of a stressful few months for her family. West was hospitalized for exhaustion and has been working to conquer his mental health issues after what sources called “a mental breakdown,” while Kardashian West has remained out of the spotlight since she was held at gunpoint and robbed in her Paris hotel room on Oct. 3.
Kardashian, 37, rocked an American flag bandana and an oversized jean jacket for her party. But some of her friends didn’t exactly understand the theme.
“I didn’t get the memo,” Atkin, donning a glamorous cheetah-print coat, said in one video posted to Kardashian’s Snapchat and Instagram. “I didn’t realize was Fast & Furious meant. I thought it was fast and fabulous!”
Meanwhile, Achemyan sported an oversized Army print jacket over a black bodycon skirt and crop top. In one Snapchat post, Kardashian captioned a photo of her makeup artist friend riding a scooter, “THOT life.”
Kardashian also took to her Instagram account to share a selfie of the trio. “Fast and furious,” she wrote in the caption.
At one point during the night, Kardashian’s guests raced on their scooters, as seen in one of her Snapchat video posts.
Clearly prepared for the holiday season, Kardashian’s trees were covered in white lights and she had an American flag pennant banner hanging inbetween them. And her backyard — usually featuring exercise equipment during her intense workouts with younger sister Khloé Kardashian — had a “The Fast and The Furious” balloon display, as well as several franchise-inspired games and activities.
RELATED VIDEO: Rob Kardashian Shows His Empty Home in Emotional Plea After Blac Chyna Hack
One family member who did not appear to be celebrating Mason and Reign’s birthdays was Rob Kardashian. On Saturday, the reality star brother took to his Snapchat to claim Blac Chyna “took the baby, took the whole nursery we built” while sharing footage of empty rooms in the couple’s shared home. He also said Chyna wasn’t letting him see their daughter.
“She blocked me or else I would ask to see her and she has the guard gate not letting me in the gate either. I just miss baby Dream.” In a since-deleted post, Chyna said Kardashian could come see Dream if he wanted to because he “knows where we are” and accused him of being involved in her headline-making Instagram hack earlier that day.