The Last Straw is received after the completion of the quest Best Served Cold; the version differs if either Orsino or Meredith was supported during the opening Act 3 quest Showdown.
Letter[]
Champion,
You have proven yourself a friend of order in this city, and I find myself in need of your support once again. Dire events are underway at the Gallows which could tear the city apart. I believe the Champion's appearance could make all the difference, and thus I ask you to come as soon as possible.
Knight-Commander Meredith
If Hawke supported Orsino...Champion,
You have proven yourself a friend to Kirkwall's mages and it seems I must call upon you once again. Meredith has gone too far, and I will not let her madness remain unchecked. I ask that you come to the Gallows at once. Perhaps together we can stop this before there is bloodshed.
First Enchanter Orsino