Thinking it over, this maybe could work, IF you were to have some cataclysmic event that made the political landscape unrecognizable.
Say, the Liberals suffer an even bigger defeat than the one under Ignatieff in 2011, and this is repeated in at least one more election. So the NDP takes the place of the Liberals as the main left-of-centre party, moving itself relatively to the right in the process. The Liberals are thus left as a shell of their former self, vulnerable to entryist takeovers from various interested parties, including social-conservatives. If the remaining few MPs are people like Tom Wappel, that increases the likelihood of SoCons being the successful raiders.
To make things interesting, have David Orchard(Canadian nationalist, SoCon) leading one flank of the takeover. This gives the raid a bit more left-wing credibility(of the nationalist variety), and the realigned Liberals can claim to still be fighting the good fight of Walter Gordon and John Turner(1988 version).
Like I say, this is basically a completely re-altered political landscape.