The graphics for Call of Duty: Modern Warfare 3 are focused around realism. Through the game, you’re trying to stop this from happening and kill Makarov so that peace can be brought between America and Europe with Russia.
What he wants is the codes for the nukes so they can easily take control of most of Europe. Makarov’s plan in Call of Duty: Modern Warfare 3 is to take over Europe through controlling the President by threatening the daughter to take his daughter as a hostage if he doesn’t do what he says. Nikolai being the less wounded one of the two and carries Soap to a safe house in Russia, where they receive help from a friend of Nikolai who shares the same goal to take down Makarov. So, you have been warned, just after Soap and Nikolai killed General Shepherd, the game carries on from there with both Soap and Nikolai injured from the fight. This does contain huge spoilers for Modern Warfare 2 but if you haven't played it, you should go play it and then come back to finish reading.
The plot of Call of Duty: Modern Warfare 3 carries on from the second installment of the series and starts straight where the second left off.