At approximately 5:00 pm this evening, Companies were alerted to a report of an odor of smoke in the residence within the first due. Engine 42 and Truck 4 responded with 10 personnel and investigated. Nothing was found. However, while completing investigation, units were alerted to a residential fire in District 6. C-63 arrived with a working residential structure fire with heavy smoke on the A side. He reported a fire in the garage/basement. E-42 and T-4 responded after clearing the previous incident and went to work upon arrival. While this incident was ongoing, Rescue 4 responded from the station with 4 crew members into Plum to assist with an odor of natural gas within a residence.