To my mind, this is where the rot set in, before this, the Avengers might have been at times, ridiculous, far-fetched, outlandish, eccentric or even weird and bizarre. But this is where they started to be just silly.
The replacement of Emma with Tara doesn't help but it's not all her fault, following the Divine Mrs Peel was always going to be a thankless job and to give credit where it is due, Linda Thorson did the best with what she had to work with. It's just all about her, it was getting more daft and brainless, the previously shadowy control known on various occasions as the Ministry or the Treasury or some other organisation, is known be the person known as 'Mother.' A fat bloke in a wheelchair is overseeing England's secret service and the fate of the free world is in his pudgy (and usually filled with a glass) hands.
The plots become more zany and wacky, here a drug delivered by blow gun, makes the person lose memory, never fully explained why, it's just a hook to hang segments and set pieces about Emma, Steed and Tara losing their memories. Why the villains don't just kill them is never considered except to let them run around constantly saying, "who am I?"
The partnership with Steed is changed forever here too, before his female aides were very much equals with him. In many cases making crucial solutions to the crimes with their scientific knowledge. Neither Cathy Gale or Emma Peel were ever anybody's fools.
But Tara King is very much in Steed's shadow, secretly in love and always in awe of him, she is now the Dr. Watson to his Sherlock Holmes. Oh, she can kick and fight with the best of them, but is still the lost little girl who needs Steed's help. Making her far younger than the previous women doesn't help, she never seems in command of a situation like Cathy and Emma were, even when they were powerless in front of a gun! You knew they were just waiting for their moment.
There are nice moments in this episode as it is the farewell appearance of Mrs Peel and the meeting of Emma and Tara is handled well. And you tell that at the end, Patrick Macnee was going to miss her both professionally and personally.