You control at least one nontoken creature with haste.
You have at least one creature card in your graveyard that has haste.
Breath of Fury attached to the creature on the battlefield that has haste.
Carmen's power is greater than or equal to the mana value of both creature cards that have haste.
An opponent cannot block creatures you control.
Carmen does not have summoning sickness.
Steps
Declare Carmen and the creature with Breath of Fury attached as attackers.
Carmen's second ability triggers, returning a creature card with haste from your graveyard to the battlefield.
Deal combat damage using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to another creature with haste, then causing you to untap all creatures you control and to get an additional combat phase after this one.
Carmen's first ability triggers, putting a +1/+1 counter on it and causing you to gain 1 life.