Grandpa Henry Reagan Visits Danny & Sean

Reagan family patriarch Henry arrives in Boston on Friday’s “Boston Blue,” ostensibly to catch up with old cop friends. But the true reason for the visit isn’t revealed until the episode’s final moments.

Len Cariou’s beloved “Blue Bloods” character is first seen early in the hour, but his appearance takes a backseat to the case of the week, which sees Rev. Peters shot after being caught in the crossfire — not to worry, he pulls through — and the subsequent arrival of Mae’s older sister Jill (played by Holly Robinson Peete). While sifting through family archives, Mae discovers that their mother, whom she believed had died in a car accident, actually died by suicide from a drug overdose. Jill was the one who found their mom unconscious on the floor, but Rev. Peters chose to shield Mae from the truth, and Jill went along with it. Mae is understandably hurt, telling Jill she’ll need time to process this newfound reality.

So soon after receiving closure regarding the murder of her husband Ben — and even sooner after her father was gunned down outside his church — Mae is once again forced to reckon with profound loss, pouring salt in an old wound.

Henry’s visit, meanwhile, is far more lighthearted. He reunites with his grandson Danny and gets to see his great-grandson Sean on duty. Seeing him in uniform for the first time in person, he references Tom Selleck’s Frank, telling Sean, “If your grandfather could see you now….”

But that’s not why he’s really in town. Back at the Silver residence, he reveals that he’s there to help smooth Danny’s transition to the BPD.

“I have a friend at Boston HQ who tells me that a certain lieutenant with 25 years on the job has the exact same number as Danny’s old shield,” he says. “So I figured that if I gave him a bottle of scotch with 25 years on it, we could make a fair trade.”

As such, Danny may have to turn in his NYPD shield, but he’ll get to retain the same number — and the gesture brings him to tears. But before Danny can officially become a Boston detective, he’ll have to serve a shift in uniform, which, as series co-creator Brandon Margolis previously told TVLine, “is something we definitely plan to explore as an episode idea in the back half of the season.”

Want more scoop on “Boston Blue”? Got questions or tips about another TV show? Email us at asktvline@tvline.com!