The Zannanza Affair.
In the wake of the death of Tutankhamen.
One of the strangest series of events that came from the wake of the Amarna period happened on the death of Tutankhamen. It involves a request by his widow, Queen Ankhesenamen, asking the king of Hatti, Suppiluliuma, for a son to marry, as there was no eligible replacement for her dead husband. Although there is no Egyptian record of the events, we have an account in the annals of Suppiluliuma as written by his son, Mursili II. 
I'll let Mursili II tell the story, which begins with Suppiluliuma besieging Karchemish which is in northern Syria on the Euphrates River, when the queen's request arrives.
The Annals of Suppiluliuma as told by his son, Mursili II
While my father was down in the country of Karchemish, he sent Lupakki and Tarkhunta(?)-zalma forth into the country of Amka. So they went to attack Amka and brought deportees, cattle and sheep back for my father. But when the people of Egypt heard of the attack on Amka, they were afraid. And since, in addition, their lord Nibkhururiya had died, therefore the queen of Egypt, who was Dakhamunzu, sent a messenger to my father and wrote to him thus: "My husband died. A son I have not. But to thee, they say, the sons are many. If thou wouldst give me one son of thine, he would become my husband. Never shall I pick out a servant of mine and make him my husband! ... I am afraid!" When my father heard this, he called forth the Great Ones for council (saying): "Such a thing has never happened to me in my whole life!" So it happened that my father sent forth to Egypt Hattusha-ziti, the chamberlain (with this order): "Go and bring thou the true word back to me! Maybe they deceive me! Maybe (in fact) they do have a son of their lord! Bring thou the true word back to me!" 
Lupakki and Tarkhunta-zalma are two Hatti commanders.
That it was the king's wife who wrote to the Hatties suggests that she was acting in that period between the death of her husband and his burial, which was normally seventy days later, though could be much longer. The person who buried the defunct king, who performed the ceremony known as the "opening of the mouth", was the person who would become the successor. The person who buried Tutankhamen was the commander of chariotry, the aged Ay. He became Tutankhamen's heir, his "son".
It is worth considering the queen's words, "Never shall I pick out a servant of mine and make him my husband." This is an intriguing statement, for the Tuthmosid royal line had come to an end with the deaths of Amenhotep III, Smenkhkare and Tutankhamen. It is possible that Ay, whose preferred title before his rise to the throne was that of "god's father", which may mean that he was the father of a queen, perhaps Nefertiti, or it could simply imply that he was a priest. Sadly it's beyond our knowledge to say specifically who the queen may have had in mind, if she was thinking of someone specific. But let us return to Mursili's account of the events.
But when it became spring, Hattusa-ziti [came back] from Egypt, and the messenger of Egypt, Lord Hani, came with him. Now since my father had, when he sent Hattusa-ziti to Egypt, given him orders as follows: "Maybe they have a son of their lord! Maybe they deceive me and do not want my son for the kingship!" -- therefore the queen of Egypt wrote back to my father in a letter thus: "Why didst thou say 'they deceive me' in that way? Had I a son, would I have written about my own and my country's shame to a foreign land? Thou didst not believe me and has even spoken this to me! He who was my husband has died. A son I have not! Never shall I take a servant of mine and make him my husband! I have written to no other country, only to thee have I written! They say thy sons are many: so give me one of thine! To me he will be my husband, but in Egypt he will be king." So, my father was kindhearted, he complied with the word of the woman and concerned himself with the matter of a son. 
["The people of Egypt(?)] killed [Zannanza] and brought word: 'Zannanza [died (?)!'" And when] my father he[ard] of the slaying of Zannanza, he began to lament for [Zanna]nza, [and] to the god[s ...] he spoke: "Oh gods! I did [no ev]il, [yet] the people of Egy[pt d]id [this to me], and they (also)[attacked] the frontier of my country!" 
As can be seen, much of this last section is fragmentary and depends on clues from what remains in order to make sense of the passage. In fact the people responsible for the death of Zannanza cannot be reconstructed from the text. It has been suggested that Zannanza actually died from the plague contracted from Egyptian soldiers taken prisoner to Hattusa and that Suppiluliuma used the death of his son as a pretext to continue military activities against Egypt, but there are at least two points against this proposal. The first is that the plague mentioned is likely to have been brought to Hattusa after Zannanza's departure. The second is what Mursili says in the Second Plague Prayer, one of the responses to the same plague.
The Second Plague Prayer of Mursili II
My father sent foot soldiers and charioteers who attacked the country of Amka, Egyptian territory. Again he sent troops, and again he attacked it. When the Egyptians became frightened, they asked outright for one of his sons to (take over) the kingship. But when my father gave them one of his sons, they killed him as they led him there. My father let his anger run away with him, he went to war against Egypt and attacked Egypt... 
Suppiluliuma, despite his anger, entered into correspondence with Egypt looking for an explanation of the events. This can be seen from a fragmentary letter found in which he responds to the new pharaoh, who is quoted as having written, "[But now] you write again and again as King of Egypt" . The Hatti king has threatened the Egyptian, who is in most analyses Ay, in his efforts to get a satisfactory reply, to which the Egyptian responds by praising of his own "[troop]s and charioteers". We know that Suppiluliuma eventually went to war with Egypt and the fighting took place where Hatti-Egyptian tensions had already flared up, in the Beqa'a, but the conflict was left to peter out. Hatti had problems elsewhere to deal with. Egypt didn't want the fight.
Trevor Bryce, analysing the situation writes in his conclusion, "How, then, do we explain Zannanza's death? Was it organized by a rival faction in Egypt opposed to the accession of a foreigner? Was the prince killed by a local group on his passage through Syria? Was his death accidental? Or was he the victim of an as yet unrevealed conspiracy? Such speculation belongs more appropriately within the realm of historical fiction." 
 The full text of the annals has been translated by H.G. Gueterbock, "The Deeds of Suppiluliuma as told by his son Mursili II", JCS 10 (1956). These tablets are part of a large archive mainly from the Hatti capital Hattusa, which included letters, treaties, annals, prayers, omens and many other text types.