Time Traveler

I succeed in deciphering the message. The key was a Russian word, just as the spy said, although as commonly spelled in English. At least, I think it was. There is at least one other keyword in English that produces the same numerical key. I tell him where the meeting place of the cell is and urge him to hurry. The police get to the meeting place in time to round up the cell. They discover that the conspirators were planning to bomb Queen Victoria's procession next. History is preserved.

I'm feeling good about this time traveling. I think it's time to tackle bigger challenges.