Sector 1 Reactor

The Sector 1 Reactor is one of the eight Mako Reactors built by the Shinra Electric Power Company to power the city of Midgar. It is the very first area visited in the game Final Fantasy VII. Its layout is exactly the same as the Sector 5 Reactor. The Sector 1 Reactor is the northernmost Reactor in Midgar, and is even referred to as the "Northern Reactor".

Storyline
The eco-terrorist group AVALANCHE, in an attempt to save the Planet from the corrupting ways of Shinra, attack the Reactor. The attacking force is made up of five people: the leader Barret Wallace, and his men Biggs and Wedge and Jessie. Coming with them is the recently hired ex-SOLDIER Cloud Strife. The team captures a train and uses it to break into the Reactor grounds, which are heavily defended by Shinra guards.

The team fights their way down into the main generator, and prepares to put the charges in. However, Cloud has a brief flashback to the incident in Nibelheim and suffers a massive psychic disturbance. This is the first sign that Cloud is not all that he seems. Before the charges can be pulled, the robot Guard Scorpion attacks and is defeated. With ten minutes remaining, AVALANCHE makes its way back up the way it came. The team escapes just before the Reactor explodes, completely destroying it and causing massive destruction. Unknown numbers of civilians are killed thanks to the explosion.

With their mission complete, AVALANCHE splits ways to avoid capture. During this time, Cloud first meets the flower girl, Aeris Gainsborough. But their meeting is brief, since Cloud must escape the guards hot on his tail. He kills or avoids the guards, and jumps onto the train that holds the other members of AVALANCHE on their way to their home base in Sector 7. Cloud would be paid 1,500 gil for his part in the successful attack.

Later in the game, when Shinra places the Sister Ray cannon inside Midgar, seven Reactors are seen working to charge up the cannon's blast. This shows that Shinra never rebuilt or repaired the Reactor following the explosion.

Items Found

 * Potion (x2)
 * Phoenix Down
 * Potion
 * Restore Materia
 * Assault Gun
 * Potion

Platform

 * MP x2 (Event)

Outside the Reactor

 * MP
 * MP x2
 * Guard Hound
 * Guard Hound (Back attack)

Reactor No.1 - Connecting Walkway

 * Mono Drive x2
 * MP x2
 * MP x2, Mono Drive

Reactor No.1 - Entrance

 * 1st Ray x2, Grunt
 * 1st Ray x3
 * Grunt x2
 * Grunt x3

Reactor No.1 - Main Staircase

 * 1st Ray x2
 * 1st Ray x2, Grunt
 * 1st Ray x3
 * Grunt x2
 * Grunt x3
 * Grunt x3 (Back attack)
 * Mono Drive x2 (Back attack)
 * Mono Drive x2, 1st Ray

Reactor No.1 - Upper Piping

 * Grunt x2, Mono Drive (Back attack)
 * Grunt x2, Mono Drive x2
 * Grunt x3
 * Mono Drive x3, Grunt x2

Reactor No.1 - Lower Piping

 * Grunt x2 (Back attack)
 * Grunt x2 (Row 1), Sweeper (Row 2)
 * Sweeper
 * Sweeper (Row 1), Grunt x2 (Row 2)

Reactor No.1 - Core

 * Guard Scorpion (Boss)

Musical Themes
Throughout the entire Sector 1 Reactor plays "Opening ~ Bombing Mission" (オープニング~爆破ミッション Ōpuningu ~ Bakuha Misshon). The theme was iconic enough that it was remixed several times, and later reappeared in Crisis Core -Final Fantasy VII-.

However, "Mako Reactor" plays inside the reactor itself, until the Guard Scorpion battle begins, where the background theme changes again to "Bombing Mission".

Trivia

 * During the mission Cloud has a moment where he breaks down and hears a voice that says, "This isn't just a reactor". In a scene that was scrapped from the final version of the game Cloud would have had a conversation with Sephiroth where Sephiroth would have explained what Mako Reactors really are. The "This isn't just a reactor" memory is a remnant of this deleted scene.