From the official FFG product page:
Enter a world where anything is possible in KeyForge! Here in the world’s first Unique Deck Game, two players become Archons racing to forge keys that unlock the hidden vaults of the Crucible, an artificial world built from pieces of countless planets. With an incredible array of creatures, artifacts, and abilities, no two decks are alike, and no two battles will ever be the same!
The Keyforge: Call of the Archons starter set is the perfect place to begin your adventures on the Crucible. As you race to gather Æmber and unlock the Crucible’s hidden vaults, you need to all the help you can get, and in this set you will find all the implements you need to begin your journey. Providing you with two training decks: Miss “Onyx” Censorius and Radiant Argus the Supreme, as well as two unique Archon Decks and a collection of keys, tokens, chain trackers, and status cards, this set provides you with everything that you and your chosen opponent need to start playing!