She was trying to figure out the truth behind his scheme with Serena (Melissa Archer), but Nicole (Arianne Zucker) will begin realizing just how much danger her association with Xander (Paul Telfer) has gotten her into on Days of Our Lives.  

Serena & Xander's Secrets Are Exposed

He has started showing his possessive and jealous side about her still very obvious attraction to Daniel (Shawn Christian), and has begun to scare her as a result, prompting her to do a deeper investigation into him. That search unearthed the shocking truth to her about his past, and the fact that he has previously been locked up for murder--meaning she could be fighting for her life if she crosses him. 

As a result, she may finally seek Daniel out and come clean to him with the truth about why she turned down another chance at romance with him in favor of one with Xander--with the hope that knowing the truth will not only make Daniel sympathetic to her case, but will give them a chance to potentially get things back on track.  

Serena Worries About Nicole's Safety

Getting Daniel back on her side could also benefit Nicole in an unexpected way as well, because when the two have worked together in the past, it has generally proven to work in their favor and keep them from getting themselves killed--making him a powerful potential ally should Xander be driven to the extreme--something which is very likely when he realizes Nicole was using him for dirt on Serena the entire time and wasn't genuinely in love with him.  

Days of Our Lives airs Monday-Friday at 1 p.m. on NBC.