Possible Clues:

• Zeroed (in on)
• ___ in on (moved toward a goal)
• ___ in on (moved toward)
• __ in on
• __ in on (neared)
• Provided with permanent accommodation
• ___ in on (got closer to)
• ___ in on (approached a target)
• ___ in on (targeted)
• Returned like a pigeon to house by the sea