What does the cryptic crossword clue "Engaged in protecting cross talisman against evil (6)" mean?

The wordplay uses a container (one word inside another). MULE (synonym="MULE") in AT (synonym="AT") = AMULET The answer is AMULET.

Engaged in protecting cross talisman against evil (6)

Independent Cryptic #11470 | 20 Down | 2023-07-17 flower