If my opponent plays Spectral Matron and I respond with Here to Help into Brynhir Thunderson, will Brynhir's ability resolve first and prevent Spectral Matron's ability from functioning?

Ruling: Yes, Brynhir's ability will resolve first and prevent the opponent from playing the unit from Spectral Matron's ability.

Sequence:

• Opponent plays Spectral Matron, its ability triggers and goes on the chain
• You play Here to Help (must be played face down so it has reaction)
• You play Brynhir Thunderson off Here to Help
• Brynhir's "while you play me" ability goes on the chain and resolves first
• Spectral Matron's ability is still on the chain but cannot resolve because the opponent cannot play cards

Nuances:

• Here to Help must be played from face down to have reaction timing