What Pokemon game is good for someone completely new to Pokemon?

My friend wants to get into pokemon and I'm unsure which game would be good for them as a beginner. They're completely new to Pokemon, The Gameplay, and basically everything besides the mascot Pikachu and some Pokemon cards. And since they told me they wanted to get into pokemon, I suggested I can lend them my 3Ds. BUT I have no idea what game would be good. All I know is they really like a brown pokemon (I think it's Eevee but they aren't sure) Do you guys have any 3Ds Pokemon games I could let them play?