Seven Angels with Seven Plagues is the heading for chapter 15. We read words like "Plague" and "wrath" or "bowls of wrath" and we fall back into a common misconception from the Old Testament that God is "angry" and "out to get us". This misconception is based on a faulty understanding of the nature of God. God is not angry: God is just. The world was made to function in a certain way. Everyone (every single one of us) has the power and ability to choose how we will live. We can live into (as best we can) the will and purpose of God for our lives and God's creation or we can live in rebellion to those purposes. In Revelation the "wrath" is the just punishment for a world in rebellion and bent on violence and destruction. There's no use complaining that God should just "fix it" and us and make everyone behave. The truth is God made a world where our actions have significance and consequence. It is a world where we have to power to choose good or evil. A world where each and every one us can work to make the world a better place or we can just let it go or we can work hard to make it a much worse place. It is a world where our choices matter. All too often we simply choose to deaden the pain, minimize the struggle and seek our own comfort and ease. When we seek to live in that kind of world we are living beyond hope. C.S. Lewis once wrote that ever choice, every decision, even thing we do is moving us toward becoming heavenly or hellish creatures.
The seven bowls of wrath from the seven angels is the continuation of the cycles of seven (seven seals, seven trumpet). Remember from before that the cycles here represent a spiraling, a continuation of the same story. The story is the conclusion of the purpose of the world. The story is the redemption of the world and justice being meted out by God and received by a world that has condemned itself by its choices.