The original Starter Set was an introduction to Dungeons & Dragons' 5th edition rules released in 2014 that included a scenario called Lost Mine of Phandelver. This better-than-average adventure for beginners, available relatively cheap in a boxed set you could buy at a bunch of chain stores rather than just dingy nerd shops, served as a gateway to D&D for a lot of people. Even the Adventure Zone podcast started out playing it.
The digital version of Lost Mine of Phandelver has been available on DND Beyond for free since 2022, but it won't be for much longer. Wizards of the Coast released a new Starter Set last year with an adventure called Dragons of Stormwreck Isle in it, and just published Phandelver and Below: The Shattered Obelisk, a longer campaign that incorporates a tweaked version of Lost Mine of Phandelver as its opening chapters. So, from October 10, they'll be replacing the free version of Lost Mine with a different free adventure called Intro to Stormwreck Isle that acts as a prologue to the newer Starter Set.
Right now, you can still claim Lost Mine of Phandelver for a cost of zero gold coins. It takes a party of adventurers from level 1 to level 5, and is set in the Sword Coast region of the Forgotten Realms, which will be familiar to players of videogames like Baldur's Gate and Neverwinter Nights. Though it climaxes in a kind of boring dungeon, it's got a solid sandbox midsection and introduces a useful home base in the village of Phandalin, which is stuffed with detailed NPCs and sidequests.
D&D's basic rules are also available from DND Beyond for free, so if you were looking to get into D&D—perhaps after playing Baldur's Gate 3, which uses the 5th edition rules with some Larian Studios tweaks—this is a convenient place to start.
