PlanetScale is an open-source database-as-a-service platform built on Vitess, which powers YouTube and other hyperscale companies, allowing for high-performance queries and connections. Prisma is an ORM that enables developers to write queries in JavaScript/TypeScript, with three products: Prisma Client, Migrate, and Studio. The guide demonstrates setting up a new database, installing Prisma, defining data models, and creating an API route using Next.js to interact with the database. It also covers deploying the database to production using PlanetScale and Netlify, allowing developers to deploy their first PlanetScale database in just a few minutes.