A great PC RPG with an accessible story for beginners is 'Kingdoms of Amalur: Reckoning'. The story is about a character who is resurrected and has to find their place in a world filled with different races and factions. It's not overly complicated and has a lot of action - packed elements. Also, the world is colorful and inviting. 'Divinity: Original Sin' (the first one) is also beginner - friendly. The story of two Source Hunters investigating a series of murders and uncovering a greater conspiracy is easy to follow. The game also does a great job of introducing the game mechanics through the story.
For beginners, 'The Elder Scrolls V: Skyrim' has a great story. It has a simple enough main quest line that can be easily followed while still offering a vast world full of side quests and lore to explore. The story of the Dragonborn and their fight against Alduin is quite engaging. Another good option is 'Stardew Valley' which, while more of a farming RPG, has a heartwarming story about starting a new life in a small town, making friends, and building a community. It's easy to get into and has a relaxing pace.