Six stratagems on a 1 Detachment Point detachment is unusual, and the design running through all of them is more unusual still: each one has a base effect and a temple-specific upgrade. Which assassins you own changes what this card does more than in any other detachment in the faction.
Prime Target (1CP, your Shooting phase or the Fight phase, Battle Tactic). Target one Agents of the Imperium unit that has not shot or fought. Each time a model in it attacks a Character unit, re-roll a Wound roll of 1; and if that attack is made by an Officio Assassinorum model against the enemy WARLORD, re-roll the Wound roll entirely. Note the upgrade is gated on the Warlord specifically, not on any character.
Hyperstimms (2CP, your opponent's Shooting phase or the Fight phase, just after an enemy unit has selected its targets, Battle Tactic). Target one Agents of the Imperium CHARACTER unit that was selected; +1 Toughness until the end of the phase, and Feel No Pain 4+ if it is an Eversor Assassin unit. The card's only 2 Command Point spend, and the Eversor clause roughly doubles what you get.
Will-sapping Salvo (1CP, your Shooting phase, Strategic Ploy). Target one Agents of the Imperium INFANTRY unit that has not shot; its ranged weapons gain [SUSTAINED HITS 1], and if it is a Culexus Assassin unit, change the Damage characteristic of its ranged weapons to 3. Read the upgrade as a change to a value rather than a bonus: it is a floor as well as a ceiling.
Orbital Oversight (1CP, your opponent's Shooting phase, just after an enemy unit has selected its targets, Strategic Ploy). Target one Agents of the Imperium INFANTRY unit that was selected. Until the end of the phase it can only be targeted by a ranged attack if the attacking model is within 18 inches, or within 6 inches if your unit has Lone Operative.
Assassins carry Lone Operative, so on the models this detachment is built around the operative number is 6, not 18. That is a very strong protection and it is the reason a lone assassin can hold a forward position.
Blind Grenades (1CP, your opponent's Charge phase, just after an enemy unit has declared a charge, Strategic Ploy). Target one Agents of the Imperium GRENADES or Vindicare Assassin unit that was charged and is not within Engagement Range. Subtract 1 from that enemy unit's Charge rolls, or 2 if your unit is a Vindicare Assassin.
Ensnaring Trap (1CP, end of your opponent's Charge phase, Strategic Ploy). Target one Agents of the Imperium INFANTRY unit within 6 inches of an enemy unit it would be eligible to charge. Your unit can declare a charge, must select one of those enemy units, and does not receive a Charge bonus this turn; and if it is a Callidus Assassin making that charge move, add 1 to its melee Wound rolls until the end of the turn. A charge outside your own Charge phase, at the price of the bonus.