The Season 7 premiere of CBS' police procedural drama, Blue Bloods, will see Donnie Wahlberg's Danny in trouble after he finds out that Robert Lewis has discovered new evidence against him in the shooting of serial killer Thomas Wilder.

Danny shot and killed Thomas Wilder in self defence, but if Robert Lewis could prove that the murder was committed to eliminate the threat he posed to Danny's family, then the police officer could be in trouble.

Another sneak peek from the premiere shows Lori Loughlin's character Grace requesting Frank to somehow prevent her son from joining the police department. She says she does not want her son to get killed the same way her husband died while serving the New York Police Department.

"Make sure Louis does not graduate from the academy," Grace says to Frank. "Kick him out, fail him, disqualify him... I don't care what you do... anything to ensure that he does not become a cop." This unexpected request is going to put Frank between a rock and a hard place as he wants to help Louis achieve his dream as well as maintain the friendship he has with Grace.

Elsewhere this season, there's a high possibility that Frank will finally find love. It has been a while since Mary passed away, and a good number of fans believe that it's high time he moved on. But last year, Blue Blood's executive producer Kevin Wade hinted at Frank staying single for a long time, saying he was too invested in his career. "He's sort of destined to be alone," Wade said. "His work sort of gets in the way of him being able to have a personal life."

The Season 7 premiere can be watched online on cbs.com or through CBS All Access. Blue Bloods season 7 is aired on Fridays at 10 pm on CBS.