Countless “Hawaii Five-O” fans hold the Christmas episodes of the elite police procedural drama in particularly fond places in the heart. Thus far, Season 10 has been emotionally wrenching, for the characters on the islands’ crime-fighting force and for the fans who follow them every Friday night. There has been no shortage of action-- this season has been more action-driven and emotional than any in the series’ run. A highway cave-in and a weapon-wielding face-off with a soon-to-be new member of “Hawaii Five-O” started Season 10. Celebrating Thanksgiving was harder than ever in the wake of Steve McGarrett (Alex O'Loughlin) losing his mother, Doris (Christine Lahti) after his valiant attempt to take her out of her life in hiding.

Nonetheless, the “ohana” spirit survived, serving up food, family healing for Junior (Beulah Koale), and even a few football tosses from Steve.

This Christmas, it seems like “Hawaii Five-O” faithful can only dream of the days when it was “Danno” (Scott Caan) his precious “monkeys,” Grace and Charlie, and Captain Grover (Chi McBride) with his brood. In last week's tenth episode, Adam (Ian Anthony Dale) put his life and career on the line, going back to his underworld allegiance in his attempt to rescue Tamiko (Brittany Ishibashi). Many fans could only cry “Why?” In front of their small screens when Adam declined to involve “Hawaii Five-O” after declaring their resources invaluable to her father, Masuda, who was killed amid gunfire in the exchange of his daughter.

Previews released today, December 13, from SpoilerTV of this week's fall finale of “Hawaii Five-O” don’t indicate much holiday warmth or easy solutions to the drastic dilemma. The peaks into "Ka i ka 'ino, no ka 'ino" (To Return Evil for Evil) depict Adam leaving his badge on the boss’ desk instead of a cheery Santa arriving with a bag of toys.

There could also be a surprise waiting for McGarrett.

Heartbreak of deception

In one of the scenes, Sgt. Duke Lukela (Dennis Chun) looks as confounded dismayed as the “Hawaii Five-O” boss, who urges Adam to “tell me you weren't involved in any way” when presented with his watch (with a personal inscription from Kono) found at a crime scene.

Every emotion seems to drain from Adam as he takes his badge and weapon out and leaves them on Steve’s desk. “What is this?” the boss can only ask. “Sorry, Steve,” are the only words that Adam offers. In a follow-up scene, Steve relates how he has “had your back” to Adam through all that has scourged him in the past. “You deserve the truth,” Adam affirms, but then says: “I can't give that to you.”

Adam knows the truth about Kenji, and how it was his shot that took down Masuda. Steve, though, knows his people and his team. Adam still knows Tamiko is in great danger, and Steve will find a way to get truth and justice from this situation. In the meantime, he may have a situation of his own.

A mystery woman out of the air

The most tantalizing and mysterious of the preview clips probably has a connection to the simultaneous, sideline story of a “ghost from McGarrett’s past” that emerges during the investigation of a tourist helicopter that is shot down (seeming to be ripped from recent headlines). The artillery involved is traced to the phantom specter.

In the scene, and apparently aging senior lady barely shuffles her way into a room from her taxi. Once there, however, she removes her prosthetic makeup to reveal a vibrant, unknown female who burns the components of her concealment in the sink. It seems that McGarrett seldom runs into simply a pleasant, friendly person from the past, despite the efforts of his team.

This mysterious lady could lead to several episodes in 2020.

The mystery is always tempting, but just for Christmas, wouldn't it be nice if the kids could come home, and the worst crime could be Steve stealing another tree for Danny from a national forest? Danny dubbed Steve “a ruiner of Christmas” back then, but this season’s festive mood may really be in danger.

After tonight's fall finale, "Hawaii Five-O" resumes with new episodes on January 3.