This is the big enchilada. All three phases of Marvel’s "Avengers" franchise have been leading up to “Infinity War” -- the culmination of 18 films of information.
As you probably know, the Infinity Stones play an important role in "Infinity War." Big, purple baddie Thanos (Josh Brolin) has been in search of these powerful stones for years -- they're remnants of the creation of the universe sprinkled throughout the galaxy. Most of the stones have been referenced in previous films, so it’s going to be a stone scavenger hunt in the upcoming film to see if Thanos can find them all and get them into the Infinity Gauntlet (a big, bejeweled glove). If he's successful, he’s probably going to destroy most of the universe. The Avengers need to protect the stones from Thanos and collect them all before he does.
What are the six stones and where is each one hiding? Here’s a recap in case you’ve forgotten: