We are presented with what seem to be five separate graphs of red and black arrows joined to each other by grey arrows. The grey arrows appearing in the background, it seems we should focus on the individual graphs at first, so we want to find what the red and black arrows represent.
Looking to the title helps here, which seems to be referencing the John Lyly proverb "All's fair in love and war". The conclusion we can draw from this is that the puzzle is concerned somehow with love and war, and the concepts are probably represented by the two different colours red and black. Furthermore black is a colour commonly associated with war and death, while red is a colour commonly associated with love. Given this interpretation, we expect a red arrow pointing from node A to node B means A loves B, while a black arrow in the same position means A kills B.
The intuitive step here is to realise that each graph represents a Shakespearean play. The title referencing a proverb from another historic English writer is a hint towards this, and the most likely graph whence one might identify the Shakespearean theme is the graph representing Romeo and Juliet, with two people in love killing themselves. It can be found that the plays are, in clockwise order from top left, Hamlet, Othello, King Lear, A Midsummer Night's Dream, and Romeo and Juliet, and the nodes can be identified as:
(Note the ambiguity present from the symmetry in the A Midsummer Night's Dream graph turns out not to be an issue by the end of the puzzle.)
Finally we must use the numbers and grey arrows present in the diagram. Noting the grey arrows trace a single path from Othello to Paris and traverse every numbered node, we realise they supply an ordering. What we should take per node must be dictated by the numbers - if we index into each node's name by its number (e.g. Othello's node is numbered 2, so we take the second letter, T), we retrieve the message THERE'S DAGGERS IN MEN'S. This is an incomplete quote from another Shakespearean play, Macbeth, whose missing final word is SMILES, somewhat aptly capturing the concepts of love and war.
|The answer is: smiles|