You should take some time as soon as you land in the Sewer to properly equip your team with armor and Materia as there is a boss battle coming up. Speak to Aeris and to Tifa in order to wake them up.
Best Bromance
Actions during this section of the game will influence the Gold Saucer Date side quest and obtaining the Best Bromance Trophy.
After the team lands in the sewer:
| Talk to Aeris first. | + 3 to Aeris |
| Talk to Tifa first. | + 3 to Tifa |
If you are attempting to obtain the Best Bromance Trophy, talk to Aeris first to give her the points.
HP: 1,800
Reward: 
Phoenix Down
Hopefully you took the opportunity to properly equip all of your team members with Materia, weapons and armor. Aps is not particularly strong. It has two attacks that are capable of dealing some moderate damage (Tsunami and Sewer Tsunami) but there are no other surprises. Both Tsunami and Sewer Tsunami also do damage to Aps when it uses them which help to end fight faster.
Aps is weak to Fire magic so keep those spells coming and make use of Cure from your 
Restore Materia (attached to an 
All Materia) to keep your party healed up.
A video demonstration of this battle is included below for reference:
Grab the Potion to the left of the starting area after Cloud, Tifa and Aeris are done talking. Go back down into the sewer and use the ladder to climb up and out onto the walkway.
Grab the yellow 
Steal Materia sitting on the ground along the pathway as you pass by. As you reach the hole at edge of the walkway you will be presented with an option two options: “Let’s try and jump down” or “Let’s not……”. Choose to jump down the hole to continue.
Go down into the lower area of the second section of the sewer and climb the round portion of the pathway towards the back. There is a ladder on the right side which you can use to climb out of the sewer area and into the Train Graveyard.
Start off by saving the game at the 
Save Point before you continue. Go through the lit up entry way into the first train car. Come out the other side and search in the barrel to receive a Hi-Potion.
Go back through the train towards the Save Point and use the rickety wooden ladder to hop onto the roof of the train car. Grab the second Hi-Potion on the roof and continue to the other next train car.
There is a broken beam lying across the two cars. Jump on the beam and take a left leading back down to the ground. There is a barrel to the north which contains an Echo Screen.
Grab it and then proceed southeast from here to grab the shining Potion in the train car.
Continue south through this train car and exit using the opening on the right side. Use the ladder to climb up onto the roof of the train and use the ladder just north of there to climb back down onto the ground.
Continue north through the two train cars and grab the Potion lying on the ground before proceeding into the next screen.
The first thing you should do is wander over to the item flashing towards the bottom left side of the screen and pick it up to receive another Potion.
Travel over to the left even further to pick up an Ether from inside the barrel.
Travel back towards the two brown trains. The train engine furthest right has an open door. Jump in and Cloud will automatically move the train forward.
Go around the backside of the train engine and regular train car and go north. Hop on the ladder to grab the Hi-Potion off the roof of the grey train car as you pass.
Jump into the second train engine (the northern most one) to have Cloud pull that engine back. Climb the ladder on the grey train car that you just ascended to pick up the Hi-Potion.
Jump onto the train engine that Cloud just moved and then down the pathway to the left. Continue left to leave the area.
As soon as you enter this area you will be thrust into the middle of a battle around the Sector 7 pillar. The Shinra soldiers are attempting to blow up the pillar to destroy the AVALANCHE hideout in Tifa’s 7th Heaven.
Aeris will not be coming with Cloud and Tifa. Her Materia has been returned to your stockpile - you can equip it to either Cloud or Tifa if you need any of it (particularly Restore Materia and Steal Materia).
Talk to the man on the left side of the screen if you need to purchase any items, such as Potions or Phoenix Downs. Save your game at the Save Point and then begin the trek up the pillar.
Climbing the stairs to the top of the pillar is easy enough. You will encounter random fights against Shinra soldiers and an enemy called ‘Aero Combatant A’ but they are fairly easy to take care of. Continue circling the stairs until you reach the top and speak to Barret once you get there.
The game will provide you with the option of entering the menu screen to equip your party. Barret will be involved in the next fight so you may wish to properly equip him and to add Materia as needed.
Barret will currently have nothing equipped but the upcoming boss fight is not very difficult so don’t spend too much time worrying about perfecting your Materia or Equipment combinations.
HP: 1,000
Reward: Ether
The battle against Reno is a fairly easy fight. His only curveball attack is called “Pyramid”. Pyramid will prevent the afflicted character from completing any actions including attacking, using items or using Materia.
Reno even tells you how to get rid of it when he says “Try and break it if you can!”. Any standard attack will remove the Pyramid and free the character affected by it.
His other attack is called “Electro-mag Rod” and it will prevent a character’s ATB gauge (attack timer) from moving for a short amount of time.
You now have access to the Steal command now that you’ve obtained the Steal Materia. Unfortunately Reno does not have anything that you can steal.
A video demonstration of this battle is included below for reference:
Speak to Barret and Tifa once the battle has concluded. The helicopter will fly away with Aeris on board and the pillar will begin to explode. Speak to Barret one more time to make a hasty escape from the pillar before it does.
