The Reagans are faced with a big challenge when Danny's past comes back to haunt him. Meanwhile, can Frank find love in the face of such difficult times?

"Blue Bloods" season 7 is set to return in a few weeks and fans are anticipating what will happen to the Reagans and their city. After all, the previous season saw Danny (Donnie Wahlberg) confronting and ultimately killing a serial killer and Frank (Tom Selleck) talking Mayor Poole (David Ramsey) out of resigning over his guilt that his accusations against the police might have ended with one officer being killed.

Open and shut cases don't always happen in law enforcement, like Danny's shooting of serial killer Thomas Wilder (Louis Cancelmi). Fans will recall that Wilder appeared to have an unhealthy obsession with the detective and had even kidnapped his niece Nicky (Sami Gayle). While Danny and Erin (Bridget Moynahan) were able to save the young woman, Danny shot Wilder to death in a bid to stop the criminal's reign of terror.

But Danny's decision to take matters into his own hands will come back to haunt him when someone from the Attorney General's office takes a closer look into Wilder's death. EW had previously reported that Michael Imperioli will be appearing for several episodes as Miller, a lawyer who will head an investigation on Danny's shooting of Wilder.

The Reagan's patriarch will also face new challenges as he continues to serve the city as Police Commissioner. According to reports, season 7's premiere episode will find Frank approached by the wife of a slain police offer who wants the senior Reagan to talk to her son and dissuade him from joining the force. As someone who comes from a family of police officers, it would be interesting to see how Frank would react to this request. Lori Loughlin of "Full House" fame has been tapped to play Grace, the police officer's widow.

There have also been reports that Frank might finally have a love interest this season. After all, he has been a widower for several years now and the writers probably think it's time for him to move on.

"Blue Bloods" season 7 will be returning to CBS on Sept. 23.