Mahāmṛtyuñjaya Mantra means the big Mantra that conquers death. In the video you can listen to Lena and me chanting it together. You can also hear Kaiya coughing, because she was sick :)
The Mantra comes from the Śri Rudram, one of the most important texts of the Veda.
The literal translation is:
We worship Tryambaka (the three-eyed God Śiva), who has a beautiful fragrance and cares for all beings. Like a (ripe) gourd falling from its stem, may he liberate us from the fea