To get an idea of the kinds of topics covered, just look up any college with a computer science department and look at their course list. For example, Stanford's is here.
In general, you'll have a couple of intro courses on basic programming, then you'll probably have courses covering: recursion and functional programming, data structures, algorithm analysis, graph theory, Turing machines and computability/complexity theory, computer architecture (how CPUs, OSes, memory/caches, disks, networks etc. work in detail), programming language design, and software engineering. For electives you might study some subset of: AI, neural networks and machine learning, compiler design, graphics, high-performance computing, user interfaces, databases, robotics, computer vision, natural language processing, and data mining.