Splinterlands is a digital, collectible card game built on blockchain technology. It is similar in concept to games like Magic the Gathering and Heartstone where you build up a collection of cards, which all have various different stats and abilities, and use them to battle other players in skill-based matches.
A player needs to have a Summoner's spellbook to activate the Play-to-earn real-valued rewards and unlock the full potential of the game. The spellbook is worth 10 USD.