"Mercy" -- Danny Reagan (Donnie Wahlberg) works on a case at the station on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Danny Reagan (Donnie Wahlberg) discuss the case at the station. Photo: John P. Filo/CBS ©2011 CBS Broadcasting Inc. All Rights Reserved.

"Mercy" -- Danny Reagan (Donnie Wahlberg) works on a case at the station on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Danny Reagan (Donnie Wahlberg) discuss the case at the station. Photo: John P. Filo/CBS ©2011 CBS Broadcasting Inc. All Rights Reserved.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here left to right: Erin Reagan Boyle (Bridget Moynahan) and Danny Reagan (Donnie Wahlberg) discuss the case at the station. Photo: John P. Filo/CBS ©2011 CBS Broadcasting Inc. All Rights Reserved.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here left to right: Det. Jackie Curatola (Jennifer Esposito), Erin Reagan Boyle (Bridget Moynahan) and Danny Reagan (Donnie Wahlberg) discuss the case at the station. Photo: John P. Filo/CBS ©2011 CBS Broadcasting Inc. All Rights Reserved.

"Mercy" -- Danny Reagan (Donnie Wahlberg) works on a case at the station on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Danny Reagan (Donnie Wahlberg) discuss the case at the station. Photo: John P. Filo/CBS ©2011 CBS Broadcasting Inc. All Rights Reserved.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here: Det. Jackie Curatola (Jennifer Esposito).

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here: Det. Jackie Curatola (Jennifer Esposito).

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here: Det. Jackie Curatola (Jennifer Esposito) talks to a potential witness.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here: Det. Jackie Curatola (Jennifer Esposito) talks to a potential witness.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position. Meanwhile, Jamie (Will Estes) goes undercover at a bar and meets a suspicious patron (Eric Morris), on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Photo: Heather Wines/CBS©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position. Meanwhile, Jamie (Will Estes) goes undercover at a bar and meets a suspicious patron (Eric Morris), on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Photo: Heather Wines/CBS©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

"Mercy"-- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position. Meanwhile, Jamie (Will Estes) flirts with Mandy (Cassidy Gifford) at the bar BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Photo: Heather Wines/CBS©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

"Mercy" -- When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position. Meanwhile, Jamie (Will Estes) goes undercover at a bar and meets a suspicious patron (Eric Morris), on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Photo: Heather Wines/CBS©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

"Mercy"-- Multiple Grammy Award-winning musical sensations Tony Bennett and Carrie Underwood perform on BLUE BLOODS. The second season episode will premiere Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Bennett and Underwood will play themselves when they perform at a fundraiser that Frank Reagan (Tom Selleck) and Erin Reagan-Boyle (Bridget Moynahan) are attending for the newly appointed mayor. Bennett and Underwood greet the Reagans before performing a duet of "It Had To Be You" for the crowd. Originally, Bennett and Underwood collaborated on this duet of the classic pop standard for Bennett's new album, Duets II, due out on Sept. 20 PHOTO by John Paul Filo ©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

When a fund raiser, who happens to be the husband of Erin's close friend, for the Mayor elect is found dead in his car, the Mayor wants Frank to position it to the public as a random act of violence, as to not jeopardize his newly appointed position, on the second season premiere of BLUE BLOODS, Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Pictured here: Frank (Tom Selleck) and Erin (Bridget Moynahan) enjoy a benefit for the mayor elect, where Tony Bennett and Carrie Underwood perform. PHOTO:John Paul Filo©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.

"Mercy"-- Multiple Grammy Award-winning musical sensations Tony Bennett and Carrie Underwood perform on BLUE BLOODS. The second season episode will premiere Friday, Sept. 23 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Bennett and Underwood will play themselves when they perform at a fundraiser that Frank Reagan (Tom Selleck) and Erin Reagan-Boyle (Bridget Moynahan) are attending for the newly appointed mayor. Bennett and Underwood greet the Reagans before performing a duet of "It Had To Be You" for the crowd. Originally, Bennett and Underwood collaborated on this duet of the classic pop standard for Bennett's new album, Duets II, due out on Sept. 20. PHOTO by John Paul Filo ©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED. PHOTO by John Paul Filo ©2011 CBS BROADCASTING INC. ALL RIGHTS RESERVED.