For a book like 'The Brothers Karamazov,' the character summaries are more useful than a plot rundown. The plot is dense with philosophical digressions, but if you understand that Dmitri is the passionate, impulsive one, Ivan the intellectual skeptic, Alyosha the spiritual seeker, and Fyodor the buffoonish father, the whole conflict snaps into focus. It's a story about three very different sons reacting to their terrible father, with a murder mystery at its core. A summary that just lists events misses the point; you need to know who these people are to understand why the events matter. The central question isn't really 'who killed Fyodor?' but 'what do these brothers believe about guilt, responsibility, and God?' That's the lens everything else filters through.
If you're pressed for time, I'd skip most online summaries that just condense the chapters. Look for an analysis, even a brief one, that lays out the core themes—faith vs. doubt, patricide, moral responsibility—and ties them to the brothers. Honestly, the subplot with the Grand Inquisitor is crucial, but a quick summary should just note it's Ivan's parable about the conflict between human freedom and spiritual authority. Trying to summarize that section itself would take longer than reading it. Focus on the family drama; the rest is commentary, albeit brilliant commentary.