I'll write a scene that occurs earlier
The Moore family arrived at a secluded, remote beach. The married couple David & Jessica along with their children Victoria (15), Bennett (14), Max & Tony (13), Cornell (12), Kelly & Halley (11), Molly (10) and Collin (7) exited their vehicle.
The kids were excited to arrive at a local beach that wasn't overcrowded with tourists and beachgoers. The couple took out their beach items and brought it to the beach.
The beach looked normal aside from a few rocks jutting out of the water and cliffs that flanked from one end to the other. The weather looked nice for a beach trip aside from a few clouds and a fog up ahead the horizon of the sea.
The family set up picnic on the sands. Jessica called the siblings, and Kelly and the others headed towards the picnic. The kids and the couple had their pleasant picnic until they finished.
Afterwards, the siblings decided to have fun. They changed to their bathing suits and had fun running around, swimming and playing with each other. It was soon clear the activities were exhausting and the family decided to rest for a while.
David and Jessica took a nap on their beach chairs while their children sat around looking at the seashore. Slowly, the tide receded, revealing a vast, wide tidal flats of mud, sand, puddles, rocks and brooklets.
Deciding on an adventure, Cornell convinced his siblings to venture out the tidal flats at low tide. However, Halley argued with her brother because she assumed going out the tidal flats would be dangerous.
At the end, Cornell and Halley agreed they can venture out the tidal flats as long as they return to shore before high tide. Soon, the siblings except for Victoria, who was sleeping on a beach chair left the safe sands of the beach towards the tidal flats at low tide.
The siblings were unaware what dangers and perils lies underneath the tidal flats...
"You hear that?" David asked groggily.
"What?" Jessica asked, stretching out on her chair.
"Exactly," David responded with a snicker.
"Did-did I, oh my gaaaawd," Jessica sputtered, now fully awake upon understanding where she went wrong.
"Finally," David laughed. "After all these years, I finally got you to say it!"
"Yeah," Jessica said before sporting a smirk of her own. "And you had to catch me when I was barely awake to do it."
"Uh, what is that supposed to mean?" David asked in a mockingly offended tone.
"Oh, nothing...Cheater."
It was only after she finished that sentence that Jessica realized how abysmal her choice of term was. Indeed, if anything could've soured the moment quicker, neither parent had an idea.
"Eh, what can I say?" David said, with a markedly colder tone. "I didn't feel like abiding rules no one else followed, y'know?"
"Davy, I'm sorry I didn't-"
"You're fine. That's just how it is," David said as he looked out to see the kids playing in the tidal flats. "Fuck, we have a lot of kids."
"I know," Jessica said, desperate to talk about something else. "I think my body still resents me to this day. I'm just glad all that child bearing didn't make me the size of our van."
"Yeah. I gotta say though," David continued with a fatherly grin. "Despite the hell they've caused, I can't help but smile every time I see all my children...and Victoria."
"David..." Jessica responded sharply as she gave him a glare.
"What? That's not an insult to her," he said, turning his head to glare right back at her. "That's just how it is...Wait, you hear that?"
"No, you don't get to-"
"Jessie, I'm not being cute, I genuinely hear something."
Not one second after he finished that sentence, Jessica heard it too. Granted, it was a sound she only heard in movies and TV, but there was nothing as unmistakable as the sound of an enormous tidal wave.
The Moore siblings played on the mudflats at the edge of the sea. Bennett and his younfer siblings Kelly and Tony fought each other in mudfights, Molly and Collin built mudcastles, and Cornell and Agnes ( Renamed Halley)) chased each other in the mud.
Max watched over his other siblings as a lifeguard. He made sure the siblings had to return to shore before high tide comes in and the weather goes foul. Looking at the shore, he saw some figures clad in beachwear fumbling in the mud, heading towards the seashore. He recognized them as their nephews: Rory (13), Wolfgang (11), Tomas (12), and nieces: Ruth (9), Addison (10) and Justina (12).
Max waved up his arms to greet them as the nephews & nieces slowly reaching the place where the siblings are. Rory and Ruth were children of their aunt Erin, Tomas and Justina were children of their uncle Pedro, and Wolfgang and Addison were adopted German son and Japanese daughter of their queer aunts, Diana and Jade.
Off-guard from Max's sights, Cornell and Agnes chased each other as far away as possible. They ran until one of them slipped on a muddy ledge and sunk into a deep patch of mud, screaming. And the tide was quicklt rising fast.

Hello aspiring writers, I've created a Writing Game on the Writer's Block Forums. It's a collaborative writing game where each user or player takes turns writing a portion of a story. The main purpose of the game is to hone the writing skills and have fun writing.
The rules of the game are simple:
Now that I am clear with the rules, let's begin the writing game:
Against the Tide
Genre: Horror-suspense
Synopsis: When a family on a summer vacation decides to venture out a vast tidal flats at low tide, their adventure is cut short when they get themselves into danger when the tide rises. Without any rescue coming, the family is forced to endure and battle hypothermia, exhaustion, drowning, sinking in mud and sand, treacherous tides, animals, fear and discord.
The Moore family ran for their lives against the rushing, rising tide. The family consisted for married couple David & Jessica, and their children Victoria (15), Bennett (14), Max & Tony (13), Cornell (12), Kelly & Halley (11), Molly (10) and Collin (7).
They were cold, shivering and covered in muck from the sand and mud of the tidal flats. They trudged and waded through the sinking sand and mud while sprinting, splashing on the puddles of seawater left in the previous high tide.
The parents and the older children still had vigor, but the younger children lacked energy left and the young ones tumbled and floundered in the mud and sand. They were running towards the shore in a vast, expansive tidal flats at low tide, now turning into high tide. The shoreline, the beach they had first started, felt faraway and many, many miles away in their senses.
The sunny weather was increasingly becoming cold and cloudy with a chance of heavy torrential thunderstorm. The frigid winds from the sea made the family shiver from the cold breeze and drizzles.
The Moore family's situation was getting hopeless. The tidal was rising rapidly along with its swift tidal bore and large waves, the weather was becoming cold and foul, they were covered in mud and already sunk in the mud multiple times and all sorts of dangers. There was no sign of the Coast Guard to rescue them
Halley recalled her last remiscience before they were ensnared in this dangerous ordeal. She recalled the time when they arrived at the remote, secluded beach at high tide, and the time when her siblings decided to venture at the deceptively safe flats at low tide while wearing their beach wear...