 Dan (Danno) Williams, while off-duty, pursues a gun-wielding crime suspect to the man s apartment. While shooting open the lock, Danno believes he inadvertently wounds the suspect fatally. While attending to the man, the wounded suspect s girlfriend takes a gun later believed to be the actual weapon that killed the suspect and flees the apartment. Danno is soon indicted and jailed. McGarrett races to find the woman and exonerate Danno.