Optimus Prime, Elita-1, Bumblebee, and Megatron ventured deeper into the cave, their optics dimly lighting the path ahead. Among the fallen, they found Alpha Trion, barely alive but conscious. He stirred, his voice weak yet urgent.

Alpha Trion: "Sentinel Prime… He deceived us. He lured us here, promising a brighter Cybertron, only to betray us."

Optimus stepped closer, his expression one of disbelief.

Alpha Trion: "We were trapped in this cave. He brought enemies… one by one, my brothers fell. He hunted us like prey."

Elita-1 knelt beside him, her face grim.

Alpha Trion: "I am the last… but I saved what I could."

He raised his hand, placing four glowing Prime cores into the chests of the group. Energy coursed through their frames, granting them the essence of the fallen Primes. As the light dimmed, a rumble echoed through the cave. Sentinel Prime had found them.

Sentinel Prime: "There you are. I always finish what I start."

Soldiers followed him, their weapons drawn, advancing slowly.

Alpha Trion: "You must leave, now! I'll hold him off."

Optimus: "We can't leave you here!"

Alpha Trion stood tall, defiant.

Alpha Trion: "My war isn't over...Go, and save Cybertron and show the truth! "

The four transformed and raced through the hidden passage. Behind them, Alpha Trion prepared for his final stand, as Sentinel's forces closed in. The cave shook with battle as they fled to safety, the weight of the betrayal heavy on their sparks.