Boston Blue Season 2 is almost here, and the familiar faces at the heart of the CBS crime drama are ready to return.The Blue Bloods spin-off follows former NYPD detective Danny Reagan (Donnie Wahlberg) as he takes a position with the Boston Police Department and is teamed up with Lena Silver (Sonequa Martin-Green), the eldest daughter of a noted police family. The second season will bring new cases for Danny and Lena, while they each navigate challenges in their personal lives.As Boston Blue Season 2 picks up where the first installment left off, the show is set to bring back the main returning cast while introducing new faces to shake up the Boston Police Department.Boston Blue Season 2 cast: Donnie Wahlberg and the returning main stars View this post on Instagram Instagram PostLike the first season, Donnie Wahlberg leads the Boston Blue Season 2 cast as Boston Police Department detective Danny Reagan. While Danny moved to Boston in the first season for his son, he had settled into his new life with his new work partner, Lena Silver. The second season will mark a new chapter for Danny as Maria Baez moves to Boston, along with her daughter Elena. As a father to grown-up kids, Danny will have to adjust to having a kid in his house again.Sonequa Martin-Green is the next returning star in the Boston Blue Season 2 cast as Boston Police detective Lena Silver and Danny's partner. While Lena deals with the sudden arrival of her biological father, TV Insider reports she will also find a new lead in Detective Brian Rodgers' attack.On the professional front, the Season 2 premiere will bring a unique challenge for Danny and Lena when a copycat killer begins a string of murders mirroring the infamous Boston Strangler, sending the city into chaos.Here's a rundown of the main returning stars in Season 2:1) Ernie Hudson as Reverend Edwin Peters, Mae's father2) Maggie Lawson as Sarah Silver, Lena's stepsister3) Gloria Reuben as Mae Silver, Jonah and Lena's mother4) Marcus Scribner as Jonah Silver5) Mika Amonsen as Sean ReaganBoston Blue Season 2 cast: Supporting actors and new additions View this post on Instagram Instagram PostIn addition to Donnie Wahlberg and the returning main stars, Boston Blue Season 2 will also mark the return of stars Ryan Broussard as Detective Brian Rodgers, Erik King as Lena's biological father Crispus “Chris” Williams, and Alisha Wainwright as Chris' daughter, Kristina.Rounding out the supporting cast for Season 2 are Blue Blood alums Marisa Ramirez and Len Cariou, who will reprise their respective characters as Danny's girlfriend, Det. Maria Baez and Danny's grandfather and retired NYPD Police Commissioner Henry Reagan. While Maria will move in with her daughter to Boston, Henry will help his grandson and great-grandson catch the copycat killer.New additions in Season 2According to TV Insider, the Boston Blue Season 2 cast is expanding with newcomer Marg Helgenberger (CSI: Vegas) as Sarah’s estranged mother, Gwen Silver. Gwen is a complex yet charming woman who will arrive in Boston to meet her daughter.Gwen's arrival suggests that the upcoming season will serve up some intense family drama.Additionally, Eleanor and Penelope Yataco have joined Season 2 as Elena Baez, the adopted daughter of Maria Baez.Lastly, the Boston Blue Season 2 cast also has a blast from the past. Blue Bloods alum Will Estes, who played Danny's brother, NYPD Sergeant Jamie Reagan, will also appear in a guest role.Tune in to the Season 2 premiere on CBS on October 9.For the latest scoops on your favorite TV shows and movies, follow SoapCentral.