Khloé tells the women that she's had some trouble getting in touch with her brother. She asks Kris how long it's been since Chyna and Rob last spoke, and says it seems like he hasn't been at Chyna's house lately.

"I don't know," Kris said. "But I talked to Chyna and it scared me because it was everything that we had experienced with him, she was experiencing the same thing. So she wrote me last night and she said, 'Can I see you tomorrow? I just really need to talk to you, Rob won't talk to me.'"

The clip doesn't explain why Rob was MIA, but it does reveal that when he wasn't talking to Blac Chyna, he wasn't talking to anyone.

The mid-season finale of Keeping Up With the Kardashians airs on E! this Sunday at 9 p.m. EST.