It is based on the old 'Christus Victor' model but I'm glad it is at variance with it. I was never very convinced by the idea of God tricking the devil and our debt being a debt to Satan. God doesn't have to resort to tricking Satan, pretending to pay him a debt in God's son's sacrifice because I understand Satan as a created creature like us,(Ezekiel 28:13) not there from the beginning of time. Satan can't hold power over God.
In Narrative Christus Victor, the devil is envisioned as those earthly structures outside of the reign of God. This is what Walter Wink calls 'the domination system'. Jesus saves us from the domination system through his life, death and resurrection. So this goes much wider than just the cross of the Penal substitutionary atonement theory. Jesus came to make the Kingdom visible, invite people to be a part of it and he challenged it in his own life, challenging all the oppressive structures (like violence, exploitation of the poor, sexism, classism, racism, etc) that run counter to the reign of God. Jesus' exposure of the oppression of the domination system resulted directly in his death at its hands. This death was anticipated by God and Christ, but not desired by God for the balancing of some cosmic equation. The law which is supposed to work to promote good was exposed in its inadequacy for having killed the Innocent. Jesus submitted to this evil act done against him and did not repay violence with violence and the reign of God rather than 'the dominant system' was seen as victorious in its vindication of Jesus in his resurrection. Death is impotent.
Jesus has challenged violence at every point and triumphed over it. How this model impacts us is in its asking us to confront the domination system with Jesus with the absolute certainty that we will be victorious, even if we have to suffer like Jesus did. We live as a transformed community, after the pattern of Jesus. We are also aware of our own sin in that is is our participation in the structures that are kingdom-limiting: sexism, oppression, violence, classism, racism etc
This model is not so explicit in its articulation of justification and there is no talk of an actual divine exchange. Christ is not the sin offering of PSA. It's very different altogether.God invites us to live a Kingdom-life despite our co-operation with the 'dominant system'. This is grace. God also makes it possible for us to choose his Kingdom (pre-destination) but we must choose to accept the invitation (free will).
And so it's how this works alongside PSA articlated below by Driscoll, or not, as the case may be, that I seek to fathom: