Mass Effect 3 - Last Mission, Second attack on Earth, Destroy Reaper defending access to Conduit

Mass Effect 3, engineer, insane level, Last Mission, Second attack on Earth, Destroy Reaper defending access to Conduit. Description: The only way to the Citadel is through the Conduit on Earth which is guarded by a Reaper. Without destroying the Reaper Shepard cannot arrive to the Citadel.