During the Galactic Civil War, which pitted the Galactic Empire against the Rebel forces, a pair of pilots from the Rebellion, flying T-65B X-wing starfighters, were on patrol duty close to Scarif. It was then that they came across the Galactic Empire in the process of constructing the Death Star.
Back in 21 BBY, the Galactic Republic initiated the construction of the Death Star. This construction took place in orbit around the planet Geonosis. Later, in 9 BBY, the project was relocated to another planet and its corresponding orbit, where preparations were made to install the last piece.
Mon Mothma tasked the two reconnaissance pilots with uncovering the Empire's activities. They executed an early hyperspace jump, followed by another jump, only to emerge into a scene dominated by a fleet of Star Destroyers and the Death Star itself. Immediately, they were intercepted by TIE fighters. Scout Three sustained damage, prompting Scout Two to instruct his astromech droid, R4, to transmit the scans of the newly discovered space battle station, the ultimate weapon, to Base One on Yavin 4. Unfortunately, he became trapped and was struck by a Star Destroyer.
The Rebel forces were unsuccessful in transmitting the scans to their base. Subsequently, Mothma and General Davits Draven initiated a separate mission to extract Jyn Erso from the Imperial prison located on Wobani, with the intention of bringing her to their headquarters. There, she was informed about her father's involvement in the creation of a superweapon and presented with a choice: assist the Alliance in finding Saw Gerrera on Jedha, or return to imprisonment. In return for her cooperation, the Alliance promised to wipe her slate clean. Jyn accepted and met with Gerrera on Jedha, where she discovered a recording from her father revealing that he had intentionally incorporated a critical flaw into the Death Star, the Empire's planet-destroying battle station. The only method to uncover this flaw was to retrieve the Death Star plans from the data vault situated within the Citadel Tower on Scarif.
Initially, the Alliance, feeling overwhelmed by the Empire and its battle station, declined to deploy its forces to Scarif. Defying these orders, Jyn and Andor spearheaded a team known as Rogue One with the goal of stealing the plans from Scarif. Upon learning of their actions, the Alliance High Command dispatched its own forces to participate in the Battle of Scarif. Rogue One successfully acquired the plans and transmitted them to the Alliance Fleet, but at the cost of their entire team, as the Death Star targeted and destroyed the planet. The Alliance analyzed the plans and utilized them to destroy the Death Star during the Battle of Yavin, achieving the very objective they had hoped for when they liberated Jyn from custody.
The revelation of the Death Star is the central theme of Rogue One: Recon A Star Wars 360 Experience, an immersive 360 experience brought to life by ILMxLAB and distributed by the telephone company Verizon.