It’s been nearly four years since we’ve seen a One Chicago crossover, and more than five years since we’ve had one that spanned all three shows: Chicago Fire, Chicago P.D., and Chicago Med.

Even NBC has tacitly acknowledged that’s too long, and now, we’re just weeks away from a new One Chicago crossover, a January 29 three-hour event involving a gas explosion at a high-rise.

With excitement building for that three-parter — and with all three shows returning with new episodes on Wednesday, January 8 — we’re ranking the franchise’s prior crossovers, even those including Law & Order: Special Victims Unit, by the plausibility of their premises.

Check them out below, sorted from most contrived to most credible.