No Stone Unturned
From Halopedia, the Halo wiki
No Stone Unturned is the twelfth track (Disc 2 Track 3) included in Halo 3: ODST Original Soundtrack, and plays in the Halo 3: ODST campaign level Mombasa Streets. It is composed of Cast Aside (0:00-1:33), Nox Aeterna (1:33-2:39), and Marching On (2:39-3:21).
Cast Aside (1:33) is the full version of Yet Alone (from the earlier track Overture), which was first played in the opening scroll of Halo 3: ODST. It opens with a tranquil and flowing melody by the piano, soon joined by strings. The strings play a soft flowing melody before being woodwinds enter as an accompaniment. Strings then repeat the strings melody. The piece plays in the campaign level during the cutscene following NMPD HQ and continues into the gameplay sequence afterwards.
Nox Aeterna (1:06) is a shortened version of We All Got Secrets (from the later track Data Hive). It features synth effects and digital chimes, accompanied by a muted synth melody. The piece plays randomly when roaming in Mombasa Streets.
Marching On (0:42) cuts in with percussion. The percussive beats maintain a high tempo until the end. The piece plays randomly when roaming in Mombasa Streets.