Aristotle considered ‘story line’ and ‘plot’ to be the key ingredient in drama, not character.  More precisely
“Tragedy is not an imitation of persons, but of actions and of life. (…) The events, i.e. the plot, are what the tragedy is there for, and that is the most important thing of all.”   Aristotle, Poetics 4.3

Moreover, Aristotle makes it clear that he is not talking about actual events, which are the subject of history, not ‘poetry’ — by which we must understand poetic drama.
“…The function of the poet [dramatist] is not to say what has happened, but to say the kind of thing that would happen, i.e. what is possible in accordance with probability or necessity.”  Aristotle, Poetics 5.5

“…Poetry tends to express universals and history particulars. The universal is the kind of speech or action which is consonant with a person of a given kind in accordance with probability or necessity; this is what poetry aims at, even though it applies individual names.”   Aristotle, Poetics 5.5

Aristotle, interestingly, says that it is irrelevant whether a certain sequence of events did, or did not, in fact happen : non-occurrence would not necessarily disqualify the event sequence in question from having validity and persuasive power. Indeed, he implies that it is more important that a certain sequence of events should be ‘probable’, i.e. contain an inner necessity, than that it should have actually taken place ! Rather than fiction (of a certain kind) being justified because it is ‘plausible’ (could have happened), Aristotle goes so far as to suggest that ‘what actually happened’ is, as it were, validated by being in conformity (or not) with what ‘probably’ would, or should, have happened. By this I understand something like Leibnitz’s ‘Principle of Sufficient Reason’, i.e. what happened should ‘contain a reason why it  was so and not otherwise’.  In what is perhaps a rather garbled translation of the original Greek, Aristotle suggests that ‘sometimes’ what actually happened really did conform to the ideal pattern (archetypal event-chain), and that it is  these sort of events and sequences of events that the dramatist should present on the stage.

“…there is nothing to prevent some of the things which have happened from being the kind of thing which probably would happen, and it is in this respect that he [the author] is concerned with them as a poet.”   Aristotle, Poetics 5.5

Certain (but by no means all) historical sequences of events do seem to have a ‘rightness’ about them which is aesthetically satisfying and which we associate with myth rather than everyday reality which tends to be both boring and shapeless. This ‘rightness’ is essentially an aesthetic (or perhaps logical?) dimension rather than a moral one though we do have the revealing concept of ‘poetic justice’. It does indeed seem ‘right’ in a sort of cosmic sense that Macbeth should be caught in his own noose and he eventually takes this view himself, hence his final speech (“Life’s but a walking shadow…..” &c.) which demonstrates complete resignation combined with a sense that everything is futile anyway. It is also ‘right’ that Lear should pay for his folly and insupportable treatment of Cordelia, that Mark Antony should commit suicide even though he is a far more attractive character than Octavian, and so on and so on.
As Aristotle says, it is the archetypal event schemas with which tragedy (and comedy also) should be exclusively concerned.  In the terms of Eventrics, Aristotle is saying that he considers that ‘event chains which possess an inherent necessity’, whether they actually occurred or not, to be in some sense ‘more valid’ and ‘more real’ than ordinary actual event-chains which do not have this coherence and inner necessity. This is precisely why myths still have strong appeal : they all (successful ones at any rate) have this sense of ‘rightness’, of ‘inner necessity’, the sense that ‘justice is done’.   S.H. 23/9/12