This is my take on how the season finale 5 should have ended and a season premiere episode. Don't look for Catherine for she won't be there, but Rachel will.
Since I didn't record the season finale episode I don't recall much of the dialogue that was exchanged between Steve and Danny in the chopper. So I picked up after the blast.
THIS IS NOT A DEATH FANFIC
"Woaw!" Danny exclaimed when the blast pounded in his ears.
Suddenly the helicopter's instrument panel began to blare out warnings. Steve attempted to stabilize the chopper by pulling on its lever but the damage had been done.
"Strap on Danno, we're going down."
Danny briefly prised his eyes to grab the seatbelt and buckled up, bracing himself for the impact. In a last-ditch effort, Steve toiled to realign the glide angle at a greater degree of deceleration to lessen the brunt of the crash. Then, a splash and the chopper broke into pieces.
On land, wedding guests witnessed the huge atomic blast mushroom rising in the air.
"What was that?" asked one of the guests.
Adam, Jerry and Max all looked at each other, concerned that it was Five-0 related after Kono called in with a last-minute emergency.
Adam got on his iPhone and dialed Kono's number. She reached into her pocket, glanced at the caller ID and answered. "I'm all right."
"What was it we just saw in the horizon?"
"An nuke that Steve and Danny dropped into the ocean. They were aboard Kamekona's helicopter."
"Are they ok?"
Kono looked to her right at Kamekona who was seen frantically redialing Danny's and Steve's numbers back and forth. Finally he resigned to the grim fact that their lines were dead. His arm holding his phone dropped to the side and he turned to Kono with a forlorn expression. He sighed and shook his head dejectedly.
"We don't know yet," she quavered, trying to sound reassuring.
"What do you mean you don't know?" Adam was getting restless. "Have you tried their phones?"
"We did. The lines are dead. No answer."
"Voicemail?"
"Nothing. We'll notified the Coast Guard. Perhaps they got caught in the blast and couldn't reach land. I'm sure they're ok."
"Who are you trying to convince here?" Kono's anguish was palpable in the ensuing silence. Adam sighed inwardly and cleared the emotional lump caught down his throat. "Ok so what now?"
"Let's wait a bit before telling the guests. It's obvious there won't be any wedding today regardless of the outcome. We'll need to postpone it."
"All right. I'll just let the guys in on it. You call me soon as you have news."
"I will. I love you," she quavered with tears in her eyes.
"I love you too, Kono. Keep safe." He pressed 'end' and closed his eyes in despair.
"Adam? What is it?" Lou asked, concerned by the man's drawn features. "Something happened?"
"That blast…it was Steve and Danny dropping a nuclear bomb into the ocean. Kono says they've been trying to reach them but there's no answer."
They all turned to the horizon where the mushroom was gradually dwindling. "You mean…they crashed?" Jerry surmised.
Then a Tsunami Warning siren rented the air.
"We got to go inland and fast. Tsunami warning," Chin alerted as he gathered all the guests.
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Giant waves crashed onto shore, flooding the wedding site but luckily, no killer harbor wave hit the island.
Later that afternoon, Steve and Danny's anguished friends had gathered at Five-0 headquarters where they anxiously awaited news on the Coast Guard search and rescue unit to report back.
Then, Kono's phone rang on the table. All eyes shifted to the device, bodies frozen, unable to move an inch as they sensed a foreboding. Kono sucked in a deep breath and answered. "Kono Kalakaua (…) yes, yes I understand (…). No let us. Five-0 will take care of it. Thank you." She held the phone in her hand, staring at it for a few seconds as though pressing 'end' would doom their two lost friends.
"Kono?" Adam asked softly, wrapping a comforting arm around her shoulders. "Did they find them?"
She sniffed back a tear and shook her head. "They…they said that the helicopter went down and shattered on impact. They found debris floating but no sign of Steve or Danny or their bodies." She broke down in tears and fell into Adam's arms. "It can't be, Adam. It just can't be."
"Mom, why is aunt Kono crying?" Grace asked Rachel whose eyes were puffy red with tears. "Mom, you're crying too. Is it Danno?"
"Let's go outside, sweetheart, ok?"
As Adam held Kono, Lou and his wife, Jerry, Chin and Max all dispersed, each quietly retreating to seek a private spot to grief the lost of their two friends.