Voyager starts receiving a transmission from Starfleet, sent through the Hirogen relay station discovered in [#82 Message In A Bottle]. Because the relay station is powered by a contained small quantum singularity (black hole) as a power source, (although it is only about a centimetre in diameter it puts out almost four terrawatts of energy, and emits as much energy in one minute as most stars do in one year), Voyager cannot approach closely because it emits a gravimetric field that reaches two light-years away.

A shuttlecraft can withstand the gravimetric eddies better than Voyager.

A level-8 antithoron burst from Voyager is used to destroy the singularity's containment field. The energy released from the singularity creates a massive discharge along the relay network that disables every one of the stations.

The damaged shuttlecraft is scanned by a subnucleonic beam that disrupts navigational sensors so that Voyager would need to send out a directional beacon to guide them back.

The Hirogen ship has monotanium armor plating that scatters Voyager's transporter targeting beam.

To escape the destruction of the relay station and the Hirogen ships which are being sucked into the black hole, Janeway orders more power and to that end the antimatter injectors opened to 120 per cent, which could breach the core, but luckily it does not.

The Starfleet datastream degrades during transmission, requiring Seven to decompress the message and re-arrange it in the proper sequence.

A Voyager PADD is seen close-up in this episode. The text of the letter starts "Dear Kathryn" and those words, along with the rest of the letter, seem to be in capital letters or at least in a font with no descenders (letters which have parts that descend below the level line).

Mark's letter to Janeway;
his surname, Johnson, can be seen - previously only his first name was known

When the transmission begins degrading, Tuvok and Seven try to stabilise the signal by taking a shuttlecraft closer to the relay station. The Hirogen beam out Tuvok and Seven.

Tuvok launches a distress/homing beacon from the shuttlecraft moments before he and Seven are incapacitated prior to being taken prisoner.

the beacon is launched

( in which I also discuss source errors about this shuttlecraft.)

Tuvok works on his weekly tactical review, indicating that a weekly review is standard Starfleet practice.

It is recommended Starfleet practice to send more than one person on any away mission.

There is a latent datastream buried under the Starfleet transmission that is heavily encrypted.