This one isn’t wildly incomprehensible. It's actually a fun read (you know, as tragedies go). The problem? There are like twelve things going on at any given moment.
King Lear wants to divvy up his kingdom between his three daughters, except his favorite—Cordelia—is refusing to flatter him to convince him of her love. Lear handles this with the grace and maturity of a wise and aging ruler, so he throws a tantrum and banishes her from the kingdom. His two remaining daughters, Regan and Goneril, begin manipulating him with the help of their husbands, the Duke of Cornwall and the Duke of Some Other Vaguely Important Land. (I think everyone in this play who is not related to King Lear is a duke or an earl of something vaguely important. If this is not true, don’t burst my bubble. I want it to be true.)
There’s also a love triangle, a king’s fool, and a hamfisted bastard prince subplot, because if there’s not an illegitimate heir trying to claim what’s rightfully his, is it really a Shakespearean tragedy?