There used to be another borough of London. One that has been forgotten, intentionally. Arkenbury was hotbed of supernatural activity. A part of London where so many events occurred that L.A.N.C.E. has an entire wing of its library dedicated to reports on it.

Smog under London is one of these reports. A thick miasma is coming out of the sewers and poisoning the inhabitants of Arkenbury. The cause is something even worse than industrial pollution as a result of aggressive capitalism: A Metaphor about industrial pollution as a result of aggressive capitalism.

Cultists are up to no good in the Victorian sewer system, and whatever it is they're doing, L.A.N.C.E. agents need to stop it before the Smog consumers Arkenbury, London, or even the whole world...