Midlothian police officers responded to the 14500-block of Knox Avenue just after 10:30 p.m. for a report of shots fired and possible stabbing victims.
Responding officers learned that there had been a fight between multiple people and two juveniles.
The two juveniles, who had been stabbed with a knife, were taken to local hospitals in serious to critical conditions.
Officers took a suspect into custody. That person is being held at the Midlothian Police Station for further investigation.
Midlothian detectives are investigating. Police did not immediately provide further information.