निशाचरैः by nightrangers, सर्वैरपि by all of them, अप्रमादात् alertly, गन्तव्यम् go there, राघवस्य Rama's, वधं प्रति to slay Rama, सदा always, यत्नः effort, कर्तव्यश्च should be done.

All of you, O nightrangers, should be on the alert there and it should be always your duty to try to kill Rama.