Widely considered one of the best games of all time, Bioshock tells the story of an underwater city named Rapture.
A city built for those who wish to escape the restrictive world up above, a city where doctors can perform without the need to worry about morals.
This has led to breakthroughs in science where people are able to easily manipulate their DNA and do things like improve their strength, speed, and endurance.
The greates and most alluring of these modifications are the Plasmids. Once injected into your system these Plasmids will allow a person to do things like shoot electricity, fire, ice, and much more from your hand
After being involved in a plane crash, your unnamed character enters into a lighthouse that acts as an entrance to the city. After descending into the city you are contacted by a man who goes by the name of Atlas
who asks for your help in rescuing his family from an area called "Neptunes Bounty", a sort of submarine hangar. As you explore the city you will encounter the many types of enemies that rapture has to offer, the
most common of which is the Splicer. These people became addicted to the power of being able to change their own DNA structure that they eventually lost their minds and now wander around the city.
The most popular enemy and the one who is on the cover of the game is known as the "Big Daddy" who act as the sort of security for the city and the guardians of "creatures" known as the little sisters.
I do not think I am doing a good job describing the plot for the game so I will leave a link to the wiki right here: Link to the Wiki.
Fun Fact: the background for this page is take straight from the opening cutscene of the game, when you are first introduced to Rapture and its glory.