oh, well.
it's a cartoon.
a kid (steven) who lives with three gems warriors (women who are gems and are magic) that used to fight alongside his mother (who died).
he inherited his mothers gem (and powers).
adventure ensues!

it's set in a modern world (phones, cars, internet, fastfood), and the action is about fighting 'monsters' or steven discovering a power.

the best comparison is adventure time, but the core cast is larger, and the main character is less 'I can solve this with violence' and more 'I want to make peace in the world' and a tad more childish than finn.
10 minutes each episode, I think that episode 7 (cat fingers) is the one that got me hooked.