What the characters of ‘Age of Ultron’ have been up to since ‘Avengers’

With this many characters, it’s going to be tough to keep up with everything going on in “Avengers: Age of Ultron.”

On the difficulty scale, it ought to rank somewhere between deciphering what Disney’s upcoming “Tomorrowland” is about and pretending to be excited about next year’s “Batman v Superman: Dawn of Justice.”